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Spectral slicing optical waveguide filters for dense wavelength division multiplexing | Abstract Designs for optical waveguide filters for selecting alternate channels in a dense wavelength division multiplexing (WDM) system are described. Each filter consists of a single mode optical waveguide with N equally spaced reflectors positioned along its length. Proper selection of the mirror reflectance values gives flat-top response for both transmitted and reflected channels. Calculated transmittance and reflectance spectra as well as dispersion characteristics for the filters are presented for N as high as 12. In a design example with a channel spacing of 25 GHz, the “usable bandwidth” was 14.1 GHz. | A new process for separating high quality single‐crystal InP thin films from the growth substrate is reported. These thin films were used for transmission measurements to determine InP absorption coefficients above the band edge. Photoluminescence measurements performed on these films before and after the fabrication process verified that the high quality of the separated thin film was not affected by the fabrication process. Two n‐type InP thin films, one with a doping concentration of 1.4×1017 cm−3 (1 μm thick) and the other with a doping concentration of 3.2×1018 cm−3 (2.5 μm thick), were grown and subsequently separated from the substrate. Using these separated films, the first direct transmission measurements of above band edge absorption coefficients in doped InP films are reported in this letter. | eng_Latn | 7,800 |
EARNEST PARTNERS SELECTED AS THE SOLE SUB-ADVISOR OF THE AMERICAN BEACON EARNEST PARTNERS EMERGING MARKETS FUND | th , 2013 – EARNEST Partners (“The Firm”), an investment manager with more than $20bn in assets under management, is pleased to announce that its Emerging Markets strategy is now available as a mutual fund in the U.S. The Firm was recently selected as the sole sub-advisor of the American Beacon Earnest Partners Emerging Markets Equity Fund. | This article is dealing with simulation of deployment of EDFA optical amplifier in different positions (post- amplifier or booster, in line and pre-amplifier) used for GPON downstream, which depend essentially on the opt-geometric parameters (ions erbium density and length of the fiber doped erbium) and the effect of those parameters to optimize the performance for extending the reach up to 60 km of and with 1:128 split ratio of the GPON. The performance of this system has been evaluated in terms of the quality factor, eye diagram and the minimum of BER with various simulations by sweeping fiber length and input signal power. It has been found that, the pre-amplification was performed and found to be superior with good results to inline and post amplificationn methods. | yue_Hant | 7,801 |
Cascade stimulated emission in the sodium dimer | Abstract We have observed many stimulated emission lines near 910 nm, 1030 nm and 690 nm, when diatomic sodium molecules are pumped by a pulsed laser at 354.7 nm. A mechanism of cascade emission, which may be responsible for laser action in the 910 nm and 690 nm region, is proposed and discussed. | The authors report the realisation of a contradirectional EDFA whose 1480 nm pump beam, generated by a DFB laser diode, is recycled in it by a photoinduced intracore fibre bragg grating. Insertion of the fibre grating does not introduce any extra input coupling loss and, for the same gain and noise figure values, allows a 20% decrease of the pump power compared to the EDFA without a fibre grating. | eng_Latn | 7,802 |
Exciton-Polariton Quantum Gates Based on Continuous Variables | We propose a continuous variable analog of quantum controlled-NOT gates based on a system of exciton-polaritons in semiconductor microcavities. This can be realized by the engineering of parametric interaction between control and target polariton modes, which can be varied in time. As an explicit setup we use a system of dipolaritons, which allows for enhancement of parametric interaction by auxiliary classical fields and scalable multigate system realization. The calculated fidelity is shown to exceed 99% for realistic system parameters. | We consider the cross area of the PP_ and PSV_wave window as the best window for joint PP_ and PSV_wave acquisition in VTI media. Within the effective window, the PP_ and PSV_wave's raypathes and phase angles at all reflection points are calculated, and the reflection (or transmission) coefficients' ratios of PSV- to PP_wave solved from Zoeppritz equations are defined as the controlling factor G. Then we use G values as the main controlling parameters of joint PP_ and PSV_wave acquisition design in VTI media, determine the best receiving window of detectors by analyzing G values, and derive the method of optimizing the receiving window for acquisition of multi_component converted seismic data in VTI media. | eng_Latn | 7,803 |
Quantum trajectory approach to transient behavior of injection-locked sub-Poissonian lasers | The method of quantum trajectories is adopted to the problem of laser generation with variable number of active media atoms in the cavity. The approach is applied to an injection-locked sub-Poissonian laser. The onset of laser oscillations is studied for the case of simultaneous start of the injection and pumping. It is shown that in this case the generation regime reached, where the intra-cavity intensity goes down with increasing the synchronization. | Abstract : The operational conditions of two spacecrafts performing a rendez-vous in geostationary orbit are given with the relative motion equation and the relevant control law. The concept of position, velocity and attitude measurement of the chaser vehicle with respect to the target one is given in order to allow the evaluation of the measurement errors. Simulations show the effect of the errors sources on the flight path of the approaching vehicle and point out the necessity of a good matching between the sensor accuracy and the minimum impulse level of the actuation system. (Author) | eng_Latn | 7,804 |
Amplitude range analysis of otolithic organ responses. | Benign paroxysmal positioning vertigo is easily diagnosed with the Dix-Hallpike maneuver. It is an ideal clinical condition in which to study the electrical response of the inner ear with electrocochleography techniques. Responses can be recorded during head tilt in roll and in pitch. With this technique we found that the amplitude range and scaling behavior of recorded raw data for the baseline resting position versus the stimulus position was statistically different in both patients and normal subjects. This can be demonstrated in the visual format of box plots. This technique promises to become a valuable addition to electrical examination techniques of the inner ear. | An improved model of an optical phase-locked loop (OPLL) is presented. Based on this model and rate equations of an external cavity semiconductor laser, the effects of OPLL feedback on the FM noise and the AM noise of the external cavity semiconductor laser are discussed. A new linewidth formula of the local laser is derived.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. | eng_Latn | 7,805 |
Development of Malignant Melanoma after Repeated Topical Photodynamic Therapy with 5-Aminolevulinic Acid at the Exposed Site | We report the case of a 82-year-old man who, after multiple treatments with aminolevulinic acid photodynamic therapy for solar keratoses and superficial squamous cell carcinomas, developed malignant melanoma at the exposed site on the scalp. | Two types of powerful, continuous action gas lasers are being most actively developed at the present time: the electrical discharged and the gas dynamic lasers. IVTAN research workers proposed a new method of generating laser beams - a magnetohydrodynamic method. As working fluid an MHDL may utilize a mixture of He + CO/sub 2/ with the addition of easily ionized atoms. The work conducted at IVTAN since 1970 is described. The preprint consists of two portions: the first is dedicated to the theoretical examination of MHDL: calculations of optimum lasing medium compositions, examination of various flow modes, calculations of amplification coefficient, and of MHD laser emission intensity. In the second part the results of the experimental studies of MHDL are discussed. The main result is that the lasing effect was obtained for the first time in an MHD laser. | eng_Latn | 7,806 |
Labetalol steady-state pharmacokinetics in hypertensive patients. | Abstract ::: 1 During chronic treatment of hypertensive patients observed mean steady-state plasma labetalol levels in ten patients were consistently and significantly higher than predicted from initial acute pharmacokinetic analysis. ::: ::: 2 Mean steady-state levels varied from 36 to 183 ng/ml on a chronic dose of 200 mg twice daily. ::: ::: 3 Patients with lower steady-state levels on a fixed dose of labetalol usually required higher maintenance doses to control blood pressure. | An experimental study on wavelength stability of laser diode(LD) was presented,which was based on the wavelength-temperature relationship.An ultrahigh wavelength stabilization was designed by adopting a new integrated semiconductor LD module with a wavelength-monitor.There have no use for other additional devices in this design.The wavelength drift is compensated through temperature,and the wavelength real time lock is realized.Enhancing the bias current and changing the setting temperature were employed to test the characteristic of the system.Experiment shows that the wavelength stability is less than or equal 2 pm,and that the wavelength control precision is less than or equal ±2 pm. | eng_Latn | 7,807 |
Enhanced second-harmonic generation efficiency in a waveguide-coupled photonic nanocavity | We investigate second-harmonic generation (SHG) efficiency in a waveguide-coupled photonic nanocavity. The factors for highly-efficient SHG are analyzed. It is found that 100% efficiency is achievable by introducing a mirror at the waveguide. | Abstract A simple method to engineer qutrit state with biphotons is realized. The method is based on Hong–Ou–Mandel interferometer and it is insensitive to disturbance comparing to Mach–Zehnder interferometer in principle. Moreover, a tomography procedure is employed to reconstruct the output states. | eng_Latn | 7,808 |
New tapered quantum-dot mode-locked laser diode with high peak power, low divergence and good beam quality | With a fully gain guided quantum-dot tapered laser diode we demonstrate stable low beam divergence, high beam quality together with a record peak power of 2.6W under passive mode locking. | -We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GHz have been generated. | eng_Latn | 7,809 |
Anticorrelated bidirectional output of quasistadium-shaped semiconductor microlasers | Time-domain properties of the output from quasistadium-shaped microcavity semiconductor lasers are studied. Ring modes generating a bidirectional output are selectively excited by partial pumping. We observe a high anticorrelation between the two beams output from the ring modes. This can be considered as the generalization of alternate oscillations reported previously. We find that the outputs exhibit a robust slow modulation of 4–10 MHz, and explain it by the quasi-degeneracy of the resonator modes. | Abstract We derive semiclassical equations for a single-mode laser operating between a bound state and an autoionizing resonance. We study its steady state properties, find intensity-dependent frequency pulling effects, bistability and, in a certain sense, inversion-less operation. | eng_Latn | 7,810 |
Linearity and noise of InGaAs multi-quantum-well lasers | Measurements are presented which demonstrate that multiple-quantum-well (MQW) lasers can offer significantly lower noise and distortion levels than equivalent double-heterostructure lasers. Improvements of approximately=10 dB in the laser intensity noise and approximately=8 dB in the second-harmonic distortion have been achieved. These figures are close to the predicted improvement of approximately=12 dB expected in MQW lasers as a result of doubling the laser resonant frequency. > | Abstract In this paper numerical improvements are proposed to enhance the accuracy and efficiency of frequency-domain transient transmission line modeling. The adopted procedure is based on a robust eigenvector tracking algorithm and an accurate shape-preserving interpolation routine, formulating the highly resonant nodal admittance matrix from a minimal number of frequency data. The proposed method is integrated with the numerical Laplace transform and its performance is demonstrated in a configuration, consisting of an underground cable and an overhead line. Results are validated with the corresponding obtained from a frequency-domain model with regular sampling, revealing the high accuracy of the proposed formulation. The computational efficiency of the proposed numerical improvements is highlighted by comparisons of the execution times in cases of high sampling rates. | eng_Latn | 7,811 |
What is the size or volume of a photon? | What is the size of a photon? | How long does it takes to transmit data from Voyager 1 back to earth? | eng_Latn | 7,812 |
US Airborne Laser Advances to 'First Light' | A Boeing Co.-led team has successfully fired for the first time a powerful laser meant to fly aboard a modified 747 as part of a US ballistic missile defense shield, officials said on Friday. | Flarion Technologies, the architect of the Flash-OFDM mobile broadband system, that T-Mobile International, a subsidiary of Deutsche Telekom AG, deployed a trial of Flarion's system for mobile broadband ... | eng_Latn | 7,813 |
Laser Link between Artemis and Aircraft | Artemis, the European Space Agency Advanced Relay and Technology Mission Satellite, successfully relayed optical laser links from an aircraft in early December. | If the airline acquires some ATA assets, Wichita Mid-Continent could see expanded AirTran service, especially to Chicago. BY PHYLLIS JACOBS GRIEKSPOOR. | eng_Latn | 7,814 |
Boeing Wields a New Laser | According to a Pentagon announcement issued Friday, last week Boeing (NYSE: BA) successfully completed a test of one of the coolest weapons ever designed (not their exact words). | Solar-wafer maker allays investor concerns of rising costs. | eng_Latn | 7,815 |
Development and future prospects of terahertz technology | Recently, the technology of terahertz (THz) waves, which have been called undeveloped electromagnetic waves, has been making remarkable progress. In addition to the technologies of generating THz waves using lasers, which are promoting this progress, advances are being made in THz generation methods using electronic devices and accelerators, and various THz optical components have been actively developed. The applications of THz technology are also becoming increasingly widespread. In this report, I will review these developments and discuss the future prospects of this field. | Abstract We report ESR experiments on a LaAl 2 sample doped with 6% Gd. The experiments were performed at 1, 3, 9 and 35 GHz. We find for T ≈ T c essentially a frequency independent shift of H res , but a frequency dependence for the minimum in the linewidth. The results will be discussed in terms of static internal fields and dynamic field fluctuations. | eng_Latn | 7,816 |
Erbium doped glasses for optical fiber amplifiers | The optical and physical properties of three different glass systems were presented. The obtained glasses were doped with 1,75wt% erbium oxide (Er2O3). Transmission and luminescence spectra were measured. Absorption spectra were calculated on the basis of transmission spectra. Classic active optical fiber doped with 1,75wt% erbium oxide was fabricated. Attenuation of fabricated optical fiber was measured.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. | Abstract Employing Glauber's approximation and optical potential, the angular distribution and vector and tensor polarization for the scattering of 420 MeV deuterons from carbon are calculated and compared with the experimental data of Button and Mermod. | eng_Latn | 7,817 |
Refractive management of ametropia | Clinical Analysis and Management of Ametropia Myopia Hyperopia Astigmatism Anisometropia Low Ametropias Presbyopia Glossary | We study the photorefractive self-action of light beams within an iron-doped planar optical waveguide in lithium niobate biased by external electric field, to find the conditions for the formation of quasisteady-state screening-photovoltaic spatial solitons. Their formation is expected to take much shorter time compared with the steady-state photovoltaic solitons. | eng_Latn | 7,818 |
Extraction of circuit parameters from time stepping FEM computation for coupled field‐circuit simulation | Purpose – To provide a general method for coupled simulation of electrical machines and circuits, using finite element analysis and a circuit/system simulator.Design/methodology/approach – The electrical machine is modelled by dynamic inductance and electromotive force (EMF), which are determined by finite element analysis and updated in time‐stepping procedure. Calculation of these parameters is based on current perturbations that are applied on linearized field equations after determining the operating point by nonlinear analysis.Findings – Based on the case studies, the presented method can be utilized in coupled field‐circuit simulation and the results correlate with those obtained by other known methods. The results were also validated according to experimental data.Research limitations/implications – Calculation of the EMF and the presented implementation for SIMULINK have some limitations regarding the accuracy and stability of the numerical integration. In the future, the numerical methods could b... | A fiber Fabry-Perot interferometric (FFPI) temperature sensor system with digital signal processing scheme is introduced. Major functions of this digital processor is to determine the difference between the round trip optical phase shift of the sensor and reference FFPIs as changes occur in the temperature at the sensor location. The interference fringe shift caused by thermally induced chirping of laser diode light source is utilized in this scheme. The system is developed as a stand-alone instrument which has its own LCD display and a control keyboard.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. | eng_Latn | 7,819 |
A universal pre-compensation method for OFDM-based analog fiber-wireless fronthaul system | We propose a novel scheme based on uneven mapping to reduce the PAPR of OFDM signal and verify its availability by transmitting 10 × 20MHz LTE-A signal. The results show that this method could achieve 2% the EVM performance improvement. | We investigate the spatial quantum properties of the light emitted by a perfectly spatially degenerate optical parametric oscillator (self-imaging OPO). We show that this device produces local squeezing for areas bigger than a coherence are that depends on the crystal length and pump width. Furthermore, it generates local EPR beams in the far field. We show, calculating the eigenmodes of the system, that it is highly multimode for realistic experimental parameters. | eng_Latn | 7,820 |
The first demonstration of an optically steered microwave phased array antenna using true-time-delay | The concept of true-time-delay steering for phased array antennas and its advantage over phase shifters in broadband applications are described with particular emphasis on the potential advantages offered by fiber-optic delay lines. The system architecture of the phased array antenna and the design and performance of the fiber-optic time-shifter networks in the antenna are described. The radiation patterns of the phased array antenna at L and X bands are presented. Using semiconductor laser switching to implement the delay times, the absence of beam squint in the antenna pattern and its frequency was switched from L to X band is demonstrated. > | We present what is to our knowledge the most complete 1-D numerical analysis of the evolution and the propagation ::: dynamics of an ultrashort laser pulse in a Ti:Sapphire laser oscillator. This study confirms the dispersion ::: managed model of mode-locking, and emphasizes the role of the Kerr nonlinearity in generating mode-locked ::: spectra with a smooth and well-behaved spectral phase. A very good agreement with experimental measurements ::: of pulse energy, spectrum, and temporal width of extracavity compressed pulses is found. | eng_Latn | 7,821 |
Bandwidth enhancement phenomenon of a high-speed GaAs–AlGaAs based unitraveling carrier photodiode with an optimally designed absorption layer at an 830nm wavelength | In this letter, the authors introduce a GaAs∕AlGaAs based unitraveling carrier photodiode (UTC-PD) for a wavelength of around 830nm. There is significant bias- and output-current-dependent bandwidth enhancement phenomena observed with this device. According to their microwave and optical-to-electrical measurement results, such distinct phenomena can occur under a much lower current density (0.3mA∕μm2 vs 0.05mA∕μm2) than previously reported for InP–InGaAs UTC-PDs. This can be attributed to the self-induced field in the absorption region, made possible due to the optimized p-type doping profile. | A new approach to the creation of a quantum cascade laser is suggested, which employs interband transitions in quantum wells with a coherent electron transport. The coherent electron transport is studied based on the simplest two-band Kane model, in which the interaction between states of the conduction and valence bands is described taking into account only states in the light hole subband of the valence band. | eng_Latn | 7,822 |
Receiver Design for Optical PPM Systems | An optimum receiver structure for optical PPM systemics is considered and from this a simple sub-optimum receiver is proposed which offers significant SNR improvement relative to existing design approaches and yet requires few circuit changes. Receivers incorporating either p-i-n or avalanche photodiodes and FET or BJT preamplifiers are analyzed. The optimization technique relies on matching the frequency response of the receiver to that of the incident optical pulse and setting the avalanche gain and threshold detector at optimum levels. For a FET preamplifier the SNR improvement is 10.8 dB with a p-i-n photodiode and 4.7 dB with an avalanche photodiode. For a BJT preamplifier the SNR improvement is 3.1 dB and 2.3 dB with the p-i-n and avalanche diodes, respectively. | This paper explains the way how to use the opto-coupler of interface grade with SPI bus in the control system in order to strengthen the noise rejection feature of the system. | eng_Latn | 7,823 |
Distortion in a semiconductor laser overmodulated by a sinusoidal current | When a semiconductor laser is overmodulated by a sinusoidal current, distortion occurs in the optical signal. Using a static limiter as a first model for the laser only permits a rough analysis of this effect. In order to describe the additional distortion arising when the optical intensity rises above threshold, an improved dynamic model is proposed which includes hysteresis. | A new Monte Carlo simulation tool, called PetDetSim and its experimental validation is presented. The simulation environment aims to model PET detectors and applies the Detect2000 code. Light output of LYSO and GSO crystal pins of different size and surface finish, covered with diffuse or specular reflectors was experimentally determined and compared with the results of the simulations. By improving the model concerning the pin and reflector geometry and the wavelength dependent reflection of the photocathode, the figure of merit could be considerably improved. The initially 34% deviation between simulation and measurements decreased below 11% for all LYSO crystal configurations. | eng_Latn | 7,824 |
MWIR and LWIR megapixel QWIP focal plane arrays | A mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 1024x1024 pixel quantum well infrared photodetector (QWIP) focal plane array has been demonstrated with excellent imagery. MWIR focal plane has given noise equivalent differential temperature (NETD) of 19 mK at 95K operating temperature with f/2.5 optics at 300K background and LWIR focal plane has given NEDT of 13 mK at 70K operating temperature with same optical and background conditions as MWIR array. Both of these focal plane arrays have shown background limited performance (BLIP) at 90K and 70K operating temperatures with the same optics and background conditions. In this paper, we will discuss their performance in quantum efficiency, NETD, uniformity, and operability. | OBJECTIVE ::: To establish a new method to discriminate Aaron's beard by Fourier transformation infrared spectrometry. ::: ::: ::: METHODS ::: Attenuation Reflection-Fourier transformation infrared spectrometry with clustering analysis was used to the identification of Aaron's beard. ::: ::: ::: RESULTS ::: There were obvious differences in Aaron's beard. The results are consistent with that of morphologic study. ::: ::: ::: CONCLUSION ::: This method is rapid, simple and economical, and can be used to the quality control. | eng_Latn | 7,825 |
Low-Order Stabilizing Controllers and Pole-Assignment | This paper1 considers the problem of designing stabilizing controllers of low order relative to that of the plant. It is shown that for some plants the order of stabilizing controllers may be less than or equal to l, where l is the number of plant outputs. A characterization of a set of stabilizing controllers of order less than or equal to l is given. The poles of the closed-loop system formed by the plant and low-order stabilizing controller are found to exhibit a separation property. Examples are given to illustrate the main results. | A new technique to determine the nonlinearity of high-speed photodiodes is presented. Utilizing a linearized phase-modulated link architecture, we directly measure the photodiode intermodulation distortion. Our results agree with those obtained via a phase-locked laser technique. | eng_Latn | 7,826 |
Modifying exciton optical properties in quantum dots with coherent phonons induced by ultrafast optical pulses | The distinctive effects of coherent phonons (groups of phase-matched phonons) on exciton states are reported by using single dot photoluminescence (PL) spectroscopy in semiconductor quantum dots (QDs). Coherent phonons that were induced with titanium thin metal films close to QDs by irradiating ultrafast optical pulses caused marked changes in the PL spectra including changes to the PL peak energies and PL intensities. Time-dependent reflectance measured with a pump-probe technique confirmed that coherent phonons were created at the surface of the QD sample. These results suggest that coherent phonons provide a good way to manipulate the optical properties of QDs. | The invention provides a TWDMPON uplink solution based on a tunable wavelength converter and a wavelength sharing method, comprising the tunable wavelength converter, a tunable optical filter and a circulator. The invention utilizes the tunable wavelength converter to uniformly convert an uplink time division multiplexed wavelength signal into a TWDM-PON system compatible wavelength signal, seamless compatibility of the TWDM-PON system and a traditional ONU (optical network unit) device is ensured, the outburst wavelength shift problem of the ONU is solved, and the layout cost of the ONU is effectively reduced. | eng_Latn | 7,827 |
An m-type backward-wave oscillator with photocopied delay line | Historically, microwave tubes have been fabricated from massive metal and ceramic parts. Recently, heavy emphasis has been made to lighten tubes for airborne applications. The requirements for lightweight, increased precision, and reduced costs have led to a novel approach to tube structure in which thin film technology including a photocopied process to produce a slow-wave structure on a ceramic substrate for an M-type backward-wave oscillator. Means for obtaining suitable bond of metal film to substrate without excessive rf loss is described. This paper will also discuss the problem of minimizing the sole sputtering phenomenon which degrades delay line propagation, and will report on operating performance of a 50 watt M-BWO having this type of delay line. | A new technique for CMOS class-AB output stages is introduced in this Letter. The technique uses a master---slave configuration of a complementary common-source output stage. It offers the advantage that the quiescent and minimum currents of the output stage can be independently tuned. The effectiveness of the proposed technique was verified by simulations using a standard n-well 0.18 μm CMOS process with 1 V supply voltage. A voltage buffer, that includes the proposed output stage, is able to drive a capacitive load of 0.5 nF obtaining ?63 dB total harmonic distortion. The topology features also power efficiency of about 63% for a pure resistive output load equal to 50 ?. | eng_Latn | 7,828 |
The study of SiH_4/N_2 gas discharge plasma with LIF | Mixed SiH4/N2 gas radio-frequency (RF) discharge plasma has been studied with laserr induced fluorescence (LIF). The intermediate species Si2 has been detected, and detection of Si2 in SiH4 RF discharge decomposition has not been reparted before. | Based on the small gain approximation in the unsaturated regime in this paper we present the derivation and the evaluation of the spectral optical gain, spectral noise figure and spectral quality factor on single and double pass configuration Er3+-doped LiNbO3 waveguide amplifier pumped near 1484 nm. The simulations show the evolution of the above mentioned parameters under various pumping regimes. In the present work we demonstrated that high gains and low noise figures are achievable in high pump regimes and double pass configuration. The obtained results can be used to theoretically model the optical amplification around 1500 nm in Er3+-doped LiNbO3 waveguides are function of various parameters. | eng_Latn | 7,829 |
Malnutrition-related diabetes mellitus (MRDM)--an uncommon disorder in Pakistan. | Malnutrition-related diabetes mellitus (MRDM) has been included in the classification of diabetes mellitus by the WHO Study Group due to its increasing incidence in some of the developing countries.The new category of diabetes comprises of the types previously known as tropical diabetes, pancreatic diabetes, pancreatogenic diabetes, endocrine pancreatic syndrome and ketosis-resistant diabetes of the young. Two sub-classes have now been suggested: fibrocalculous pancreatic diabetes (FCPD) and protein deficient pancreatic diabetes (PDPD). Although a large number of cases of MRDM have been reported from India, Bangladesh, Sri Lanka, Indonesia, Thailand, Jamaica, Brazil, Madagaskar, Ghana, Nigeria, Uganda, Zaire and Zambia, MRDM has so far not been reported from Pakistan. We present two cases diagnosed as fibrocalculous pancreatic diabetes (FCPD). | An apertureless near-field scanning optical microscope (a-NSOM) setup is described. Special ::: consideration is given to important system components. Surface plasmons are defined, as is their relationship to a- ::: NSOM and their interaction with the scanning probe tip. We used this set-up to measure a metal-dielectric-metal ::: (MDM) antenna integrated with a quantum cascade laser (QCL). The former is introduced and described. The role ::: of the atomic force microscope (AFM) in the experiment is laid out and explained. Finally, the lock-in amplifier is ::: explained. Next, the system setup is introduced and explained from the point of view of the light path taken by ::: light generated in the laser. Finally, results are given for the MDM single nanorod antenna and the coupled MDM ::: nanorod antenna. Simulation, topography, and NSOM images are shown. Lastly, several experimental issues are ::: discussed as well as other types of NSOM. | eng_Latn | 7,830 |
Real-time heterodyned measurements of spatio-frequency dynamics in fibre lasers | We report high-resolution real-time measurements of spectrum evolution in a fibre. The proposed method combines optical heterodyning with a technique of spatio-temporal intensity measurements revealing fast spectral dynamics of cavity-based systems. | In an earlier paper by the author the problem of determining the optimum symmetrical weighting factors for a video MTI radar was discussed. This paper extends this work so as to remove the symmetrical restriction from the problem. In addition, for a staggered pulse system, optimum times of transmission are determined. In the earlier paper a global solution to the restricted optimization problem was achieved. In this paper only a locally optimum solution is achieved for the more general problem. | eng_Latn | 7,831 |
Octave-broad ultrafast all-optical switching of silicon woodpile photonic band gap crystals | We present the first ultrafast all-optical switching measurements of photonic band gap crystals at telecom frequencies. Switching 3D photonic band gap crystals is expected to provide dynamic control of active photonic integrated circuits, over the switching-on or -off of light sources, and the capture or release of photons from photonic band gap cavities. | A novel phasor computation algorithm is presented in this paper. The real and imaginary part filters of this algorithm have identical magnitude frequency characteristic (IMFC) at all the frequencies and orthogonal phase frequency characteristic (PFC) at fundamental frequency. Considering the conditions of the same magnitude frequency characteristic (MFC) and the orthogonal PFC, the two-sample algorithm is derived. Once two-sample orthogonal filters with IMFC are obtained, the algorithm design is just to select proper shapes and lengths of windows, which determine the filtering performance and response-time, respectively. This method could be applied to design filter in any window-length, especially in short-window. Therefore, this class of phasor algorithms is suitable for EHV transmission line protection where a short-window is crucial for fast response and better operation performance. The proposed algorithm has been applied to a series of EHV relay devices by China Xuchang Relay Group. | eng_Latn | 7,832 |
Performance Limiting Effects in X‐Band Accelerators | Acceleration gradient is a critical parameter for the design of future TeV‐scale linear colliders. The major obstacle to higher gradient in room‐temperature accelerators is rf breakdown, which is still a very mysterious phenomenon that depends on the geometry and material of the accelerator as well as the input power and operating frequency. Pulsed heating has been associated with breakdown for many years however there have been no experiments that clearly separate field and heating effects on the breakdown rate. Recently, such experiments have been performed at SLAC with both standing‐wave and travelling‐wave structures. These experiments have demonstrated that pulsed heating is limiting the gradient. Also, a dual‐moded cavity has been designed to better distinguish the electric field, magnetic field and pulsed heating effects on breakdown. | -We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GHz have been generated. | eng_Latn | 7,833 |
Physical modelling of GaAs photodiodes | The bipolar drift-diffusion model of an ITO/GaAs Schottky photodiode has been used to demonstrate the importance of photogenerated charge build up within the photodiode when used in detecting high bit rate digital signals. This causes an asymmetrical response affecting the detected high and low levels which become dependent on the digital pulse pattern. Optical illumination at wavelengths <or=880 nm is through the ITO which is transparent to these frequencies. These devices have been fabricated where the depth of the intrinsic n/sup -/ layer ranges from 10 mu m to 0.45 mu m with the smallest having a reported bandwidth of 110 GHz. | We present the first ultrafast all-optical switching measurements of photonic band gap crystals at telecom frequencies. Switching 3D photonic band gap crystals is expected to provide dynamic control of active photonic integrated circuits, over the switching-on or -off of light sources, and the capture or release of photons from photonic band gap cavities. | eng_Latn | 7,834 |
Acousto-optic programmable filters and the sampling theorem | We analyze the relations between discrete RF signals and their spectra from the point of view of the sampling theorem and properties of discrete Fourier transform. The RF waveforms with given duration and spectral bandwidth are used for controlling acousto-optic tunable filters in programmable broadband transmission mode. It is demonstrated that the maximum second order dispersion of the AOTF is reduced by the factor of 2 compared to a linear chirped signal with the same bandwidth and duration. This analysis is important for applications in precision ultrafast laser pulse shaping and adaptive spectroscopy. | A method for the algebraic approximation of attractors recently developed by Foias and Temam is adapted for application to autonomous galloping oscillators. We compare results obtained by algebraic approximation on the one hand and numerical integration on the other. We conclude with an assessment of the limitations of the method as applied to our systems. | eng_Latn | 7,835 |
Curve Design of Stepper Motor and Simulation | In this paper,a control model of stepper motor after studying on its three phases hybrid drive was set up, and the potential relation between the motor speed curve and its motion performance in a real drive system was found out.Then the optimization control of precise and fast orientation of the stepper motor was given with MATLAB simulink. | We present what is to our knowledge the most complete 1-D numerical analysis of the evolution and the propagation ::: dynamics of an ultrashort laser pulse in a Ti:Sapphire laser oscillator. This study confirms the dispersion ::: managed model of mode-locking, and emphasizes the role of the Kerr nonlinearity in generating mode-locked ::: spectra with a smooth and well-behaved spectral phase. A very good agreement with experimental measurements ::: of pulse energy, spectrum, and temporal width of extracavity compressed pulses is found. | eng_Latn | 7,836 |
Symmetrical waveform generation based on temporal pulse shaping using amplitude-only modulator | Symmetrical waveform generation based on temporal pulse shaping using only an amplitude modulator is proposed and investigated. The fundamental principle of this technique is that the Fourier transform of a real and symmetrical waveform is still real and symmetrical. Therefore, it is possible to use an electro-optic modulator that is biased at the minimum transmission point to perform temporal spectrum shaping with a real signal that has both positive and negative values. The proposed approach provides a simple and effective solution to ultrashort symmetrical waveform generation. | We show <-50 dB AM-to-PM conversion over a wide photocurrent range in MUTC photodiodes. By controlling the AM-to-PM coefficient minimum, we generate 15 dBm microwave power with 60 dB AM rejection onto the microwave phase. | eng_Latn | 7,837 |
Dynamic characteristics of a semi-submersible platform with mooring system in irregular waves | Based on the coupled analysis method in time domain,the dynamic characteristics of a semi-submersible platform with mooring system in irregular waves were considered.The motion spectrums of the platform and the tension ones of the moorings were calculated and analyzed under the condition that one mooring line was broken in different wave directions.Results show that the effect of the case where one mooring line is broken on the dynamic characteristics of the semi-submersible platform in bad sea conditions will be remarkable. | -We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GHz have been generated. | eng_Latn | 7,838 |
A study on optical properties of poly (ethylene oxide) based polymer electrolyte with different alkali metal iodides | Polymer electrolytes were prepared by adding poly (ethylene glycol) dimethyl ether (PEGDME), TiO2 (nano filler), different alkali metal iodide salts RI (R+=Li+, Na+, K+, Rb+, Cs+) and I2 into Acetonitrile gelated with Poly (ethylene oxide) (PEO). Optical properties of poly (ethylene oxide) based polymer electrolytes were studied by FTIR, UV-Vis spectroscopic techniques. FTIR spectrum reveals that the alkali metal cations were coordinated to ether oxygen of PEO. The optical absorption studies were made in the wavelength range 200-800 nm. It is observed that the optical absorption increases with increase in the radius of alkali metal cation. The optical band gap for allowed direct transitions was evaluated using Urbach-edges method. The optical properties such as optical band gap, refractive index and extinction coefficient were determined. The studied polymer materials are useful for solar cells, super capacitors, fuel cells, gas sensors etc. | Abstract : We have used an optical parametric oscillator (OPO) to characterize the fiber-optic cache-memory buffers. Prior to addition of the new OPO system, a home-built saturable-absorber mode locked erbium/ytterbium-fiber laser had been used in all our experiments. With the addition of a new OPO, we are able to remedy all prior deficiencies. The tunability represents the main advantage of the system to our research program, since the cache-memory buffers and regenerators that we are developing can be used at any wavelength. This is because the response of the fiber-optic parametric amplifier is wavelength independent; the fiber nonlinearity, which is responsible for the gain, exists at all wavelengths and is not restricted to the relatively narrow range of the erbium band (1.53-1.56 microns). Thus the OPO allows us to experiment in wavelength regions that have previously been inaccessible. | eng_Latn | 7,839 |
Novel self-hybrid mode-locking of semiconductor lasers in an external cavity | A new mode-locking method called self-hybrid mode-locking is explored. This method uses RF modulation at the sub-harmonic of pulse repetition frequency so that both active and passive mode-locking mechanisms operate in the same gain region without the necessity of additional integrated absorbers. With the same cavity configuration, self-hybrid mode-locking can generate pulses about 2/spl times/ shorter than the traditional active mode-locking. | A fine structure in the 14C decay of 225Ac is predicted quantitatively by accounting dynamical aspects during the disintegration process. Transitions to the excited states of the daughter nucleus are considered to be mainly directed by the Landau–Zener promotion mechanism in the region of avoided crossing levels. The level scheme is evaluated with the superasymmetric two–center shell model. The half–lives are computed considering the cluster decay as a superasymmetric fission process. | eng_Latn | 7,840 |
Mid-infrared recognition of the reversible photoswitching of fulgides | Abstract IR absorption spectra of E- and C-isomers of several photochromic fulgide compounds were examined. As a characteristic feature, the spectra of all C-isomers show peaks that are completely missing in the spectra of the corresponding E-isomers. Photoisomerization reactions of fulgides can, therefore, be monitored and their isomerization state can be detected by measuring the IR absorption at the characteristic wavenumbers. It is verified that mid-IR irradiation using tunable IR diode lasers does not induce any photoreaction. Thus, for the application of fulgides as optical recording media or photoswitches, narrowband mid-IR absorption measurement provides a method for entirely non-destructive readout. | Abstract A simple method to engineer qutrit state with biphotons is realized. The method is based on Hong–Ou–Mandel interferometer and it is insensitive to disturbance comparing to Mach–Zehnder interferometer in principle. Moreover, a tomography procedure is employed to reconstruct the output states. | eng_Latn | 7,841 |
Modeling Simulation and Comparative Evaluation of PAPR Reduction in MIMO OFDM Scheme by Using Constant Modulus Algorithm Phase Sequence Optimization | As the demand for high-speed data communication increases, MIMO OFDM becomes more and more important. MIMO OFDM also conforms to the 4G standard because of high frequency bandwidth. Irrespective of several advantages, MIMO OFDM still continues to undergo high peak-to-average power ratio problem. This paper suggests a unique technology centered on constant modulus algorithm to mitigate the issue related to high out-of-band radiation, ICI (inter-carrier interference), and BER (bit error rate) performance degradation. The paper incorporates the simulation of the suggested algorithm in MATLAB and calculation of factors like errors and requirement of bandwidth. These factors are evaluated in contrast to modern techniques to verify the suggested methodology. | Abstract : We have used an optical parametric oscillator (OPO) to characterize the fiber-optic cache-memory buffers. Prior to addition of the new OPO system, a home-built saturable-absorber mode locked erbium/ytterbium-fiber laser had been used in all our experiments. With the addition of a new OPO, we are able to remedy all prior deficiencies. The tunability represents the main advantage of the system to our research program, since the cache-memory buffers and regenerators that we are developing can be used at any wavelength. This is because the response of the fiber-optic parametric amplifier is wavelength independent; the fiber nonlinearity, which is responsible for the gain, exists at all wavelengths and is not restricted to the relatively narrow range of the erbium band (1.53-1.56 microns). Thus the OPO allows us to experiment in wavelength regions that have previously been inaccessible. | kor_Hang | 7,842 |
Excitation of wakefields in a plasma channel by a laser pulse | The excitation of wakefields by a triangular temporal profile laser pulse with an abrupt fall in a step density profile plasma channel is investigated analytically and an exact solution is obtained. The excitation is more efficient for t~tp, where t is the rise time of the pulse and tp is the plasma period, though it is still significant for t~20 tp. The wake potential in the former case is 1.7 times the ponderomotive potential, whereas it falls to 1.4 times the ponderomotive potential for the latter. | Several types of waveguiding structures are known that can support the propagation of a finite number of bound electromagnetic modes. Two such structures are the dielectric slab and the optical fiber. In both structures the electromagnetic field associated with the bound modes extends beyond the central region; that part of the field that penetrates into the surrounding medium is termed evanescent. In this paper we use first-order perturbation theory to treat the effects caused by a surrounding medium with gain on the bound modes of the dielectric slab. A noteworthy effect is the amplification of these bound modes in accordance with formulas we present and which arises by evanescent-wave interaction with the surrounding medium. | eng_Latn | 7,843 |
Excimer laser photorefractive keratectomy for myopia: 12 month follow-up | A prospective study of excimer laser photorefractive keratectomy was performed with the aim of correcting a range of myopic errors between -1.00 and -10.00 dioptres. Corneal healing was monitored through the first post-operative year by serial assessments of refraction, contrast sensitivity, corneal haze, pachymetry and keratometry. Eighty-one patients were recruited for the study. At 12 months 81% were within +/- 1.00 dioptre of desired emmetropia and with unaided vision of 6/12. Contrast sensitivity was found by Pelli-Robson assessment to be reduced throughout the 12 months and regression analysis predicted recovery by 2 years. At 12 months, however, only 15% of patients were found to have lost a single line of best corrected Snellen acuity. Predictability of results was found to be greatest for initial errors less than -4.00 dioptres. No serious complications were observed during the follow-up period, but refraction had not stabilised in all cases and patients remain under review. | This article is dealing with simulation of deployment of EDFA optical amplifier in different positions (post- amplifier or booster, in line and pre-amplifier) used for GPON downstream, which depend essentially on the opt-geometric parameters (ions erbium density and length of the fiber doped erbium) and the effect of those parameters to optimize the performance for extending the reach up to 60 km of and with 1:128 split ratio of the GPON. The performance of this system has been evaluated in terms of the quality factor, eye diagram and the minimum of BER with various simulations by sweeping fiber length and input signal power. It has been found that, the pre-amplification was performed and found to be superior with good results to inline and post amplificationn methods. | eng_Latn | 7,844 |
Changes of PIG3 and GADD45 gene expression induced by ~(60)Coγ-rays in lymphoblastoid cells | This study is try to investigate the changes of PIG3 and GADD45 gene mRNA expression after irra- diation and the probability of them as bio-dosimeters.In the dose-effect study,lymphoblastoid cells were irradiated by ~(60)Coγ-rays with the doses of 0～10Gy and cultivated for 8 hours.Lymphoblastoid cells were cultivated for 0～72h after 5Gy irradiation for the time-effect study.The mRNA was extracted and real-time PCR method was used to detect the changes of PIG3 and GADD45 gene mRNA expression level in lymphoblastoid cells.The results show that PIG3 and GADD45 gene expression level in lymphocytes increases in a dose-dependent manner and has good dose-effect rela- tionship.The time-effect curve indicates that the peak expression of PIG3 and GADD45 is at 8h after 5Gy irradiation and then begins to decrease gradually.PIG3 and GADD45 gene are sensitive to irradiation and both of them have dose-effect and time-effect relationships. | We present an analytical derivation of the distributed model from the experimentally well confirmed lumped approach for the description of light propagation in mode-locked fiber lasers operating in the scalar regime where the dynamics is mainly governed by the propagation of a single field component. As a limiting case of the distributed model we identify the complex cubic-quintic Ginzburg–Landau equation (CQGLE). One important result consists of deriving explicit relations between the coefficients of the distributed models to the realistic laser parameters. We numerically demonstrate that the results obtained by using the general distributed model are in very good agreement with those of the lumped model, whereas results of the CQGLE can significantly deviate for a certain range of parameters. Moreover, we demonstrate that the validity of the CQGLE approach strongly depends on the operation regime of the saturable absorber. | eng_Latn | 7,845 |
Optical correlator that uses cesium vapor | We obtain the correlation pattern between two amplitude-modulated input images of 36 and 280 random black and white pixels, using the standard degenerate four-wave-mixing geometry of 852-nm optical beams in a 1-mm-thick cesium-vapor cell. The total optical input power is 3.2 mW to obtain 0.4 nW of power in the correlation pattern. We verified that the buildup time of the four-wave-mixing signal is ~30 ns. Using the random patterns, we analyze the performance of the cesium optical correlator in terms of the number of pixels that can be processed and the number of photons per pixel used. We show how to scale our experimental results for the efficiency of the cesium correlator to images containing a larger number of pixels. | Kenneth J. Rosenthal, MD, explains the advantages of an add-on sulcus-based IOL for correcting refractive errors in eyes that have undergone cataract surgery with in-the-bag IOL implantation. | eng_Latn | 7,846 |
Extremely low-noise facet-reflectivity-controlled InGaAsP distributed-feedback lasers | Extremely low-noise (relative intensity noise (RIN) < - 160 dB/Hz) was attained with the facet-reflectivity-controlled 1.3-μm wavelength InGaAsP buried-heterostructure distributed-feedback lasers, Noise increase due to the optical feedback was greatly suppressed. It was interpreted as a result of counterbalanced mode competition between distributed-feedback mode and Fabry-Perot mode. | In this paper, a new method for external disturbance rejection control which is based on the identification of transfer characteristics from an acceleration sensor is proposed. For hard disk drives, the external disturbance which should be reduced is growing with widespread use of movable computers and other independent machines. In order to reject the effect of the external disturbance, the authors apply the feedforward controller which is designed by a recursive least squares (RLS) algorithm and fixed trace (FT) algorithm utilizing the acceleration signal and the estimated disturbance signal. Some experimental results in which a disk drive is shaken in the vertical direction are shown to verify the effectiveness of the proposed method. | eng_Latn | 7,847 |
Stoichiometry-controlled inversion of circularly polarized luminescence in co-assembly of chiral gelators with an achiral tetraphenylethylene derivative | A supramolecular circularly polarized luminescence (CPL) system was constructed based on the co-gelation of an achiral tetraphenylethylene derivative and chiral organic gelators of glutamic acid in chloroform. Adjusting the stoichiometric ratio was found to be an effective strategy for regulating the handedness of CPL. | We present a hybrid-integrated coherent receiver module using flip-chip technology for coupling a silica-based 90o-hybird planar lightwave circuit (PLC) chip to a spot-size converter integrated waveguide photodiode (SSC-WG-PD) array chip for a balanced photodiode (BPD) and interconnecting with a dual-channel transimpedance amplifier (TIA). | eng_Latn | 7,848 |
Dispersion Tuning of a SOA Fiber Laser Incorporating a Linearly Chirped Fiber Grating | -We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GHz have been generated. | [1] Observations of high-latitude plasma structure and scintillation are presented from the January 2001 scintillation campaign timeframe. Comparisons are made using the all-sky imager and two beacon-satellite ground receivers located at Sondrestrom, Greenland. The Coherent Ionospheric Doppler Receiver (CIDR) observes 150- and 400-MHz signals transmitted from low-Earth-orbiting satellites. The 250-MHz polar beacon-satellite system observes signals from highly elliptical orbiting satellites. F region patches, F region precipitation arcs, and auroral arcs were observed. Intermediate-scale structure was observed on the leading and trailing edges of patches prior to exiting the polar cap. Banded structure was observed across an F region arc. Additional beacon-satellite receivers in Greenland and Alaska provide a unique opportunity to study the spatial distribution and temporal evolution of patch structures and their associated scintillation. | eng_Latn | 7,849 |
Injection lasers for far-IR spectral range | The use of far-IR injection lasers in pulsed molecular high-resolution spectroscopy is addressed. Far-IR radiation generation in a magnetoplasma spectral window is reviewed. The frequency tuning of long-wavelength diode lasers under combined temperature and magnetic field influence is examined. | The theoretical aspects of the precise velocity determination of Low Earth Orbit (LEO) satellites’ onboard Global Navigation Satellite Systems (GNSS) receivers are derived. It shows that the receiver’s Phase Lock Loop (PLL) is required to feature extremely small group delay within its low frequency band, which is in contrast to existing work that proposed wide band linear phase filters. Following this theory, a Finite Impulse Response (FIR) filter is proposed. To corroborate, the proposed FIR filter and an Infinite Impulse Response (IIR) filter lately proposed in literals are implemented in a LEO satellite onboard GNSS receiver. Tests are conducted using a third party commercial GPS signal generator. The results show that the GNSS receiver with the proposed FIR achieves 11 mm/s R.M.S precision, while the GNSS receiver with the IIR filter has a filter-caused velocity error that can not be ignored for space borne GNSS receivers. | eng_Latn | 7,850 |
Direct third harmonic generation due to quadratic cascaded processes in periodically poled crystals | Abstract We report the first, according to our knowledge, experiment for direct third harmonic (TH) generation in periodically poled quadratic crystals. TH radiation of a diode array pumped and acousto-optically Q-switched Nd:YVO 4 laser is generated in a 25 mm long periodically poled lithium niobate (PPLN) crystal of period 7.0 μm. A theoretical model is developed that explains the experimental results. It predicts that the efficient phase-matched direct TH generation in periodically poled structures with duty factor 0.5 requires even order quasi-phase matching. In contrast to the similar experiments in bulk birefringence crystals, where direct phase matched TH signal is the sum of the contribution of both intrinsic and cascaded cubic nonlinearities, in periodically poled quadratic crystals only cascaded cubic nonlinearity contributes to the direct phase-matched TH signal. | A novel 2- and 3-D space spectral domain analysis (SSDA) simulator for microstrip and CPW transmission line discontinuities is described. The characteristic impedance, effective dielectric constant, and S-parameters of different type of transmission lines and discontinuities shapes can be computed. The topology of structure and the computed results are displayed using a graphical interface. The simulator has been implemented on Sun Sparcstations. > | eng_Latn | 7,851 |
Potential of [11C]DASB for measuring endogenous serotonin with PET: binding studies | The serotonin transporter radioligand [11C]-3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile, or [11C]DASB, was examined in order to assess its potential for measuring fluctuations in endogenous serotonin concentrations with positron emission tomography. Binding characteristics of [11C]DASB and the propensity for serotonin to displace the tracer were explored in rat brain homogenates. Experiments showed that serotonin displaced [11C]DASB in vitro. Ex vivo experiments performed after tranylcypromine injection (3 or 15 mg/kg) showed a dose-dependent trend in radioactivity uptake and suggested that serotonin may compete with [11C]DASB for transporter binding. | This paper describes how to characterize the pad structure embedding silicon devices directly in terms of scattering parameters. The new procedure accounts for distributed effects associated with the structure itself (e.g. the so-called dangling source leg effect) and other coupling effects. The proposed approach is key to extending device characterization into the mm-wave range. The procedure makes use of standard structures typically available on silicon tiles without calling for measurements of additional structures. Further, it does not rely on an equivalent circuit of the structure for its characterization. The procedure is demonstrated by measurements of structures available on the Tower-Jazz semiconductor SBC13 SiGe BiCMOS process. Results acquired over the broad range of frequencies from 2 to 50GHz will be presented and discussed. | eng_Latn | 7,852 |
Differential effects of recombinant interleukin-1 alpha and beta on Leydig cell function. | Previously we have reported that human chorionic gonadotropin(hCG)-stimulated testosterone biosynthesis was markedly inhibited by purified natural human interleukin-1 (IL-1). In the present study we evaluated the effects of human and murine recombinant IL-1 (rIL-1) on Leydig cell steroidogenesis in primary culture. Human rIL-1 beta caused a dose-dependent inhibition of hCG-, 8-bromo cyclic AMP-, and forskolin-induced testosterone formation. In contrast, human rIL-1 alpha was considerably less potent. When the effects of the cytokines were corrected for their biological potencies, human rIL-1 beta and murine rIL-1 alpha were still more effective than human rIL-1 alpha in inhibiting testosterone production (at least 100-fold more potent). Thus, even though IL-1 alpha and IL-1 beta bind to the same receptors on T cells, Leydig cells exhibit differential sensitivity in response to rIL-1 alpha and rIL-1 beta which is partly species dependent. | Abstract CW-pumped Nd:YVO 4 lasers passively Q-switched with LiF : F 2 - and YAG:Cr 4+ saturable absorbers are modeled and comparatively analyzed. The model takes into account the geometric factor representing the distributions of the orientations of F 2 - color centers and Cr 4+ ions relatively to the corresponding crystalline hosts on the output parameters of the lasers. It is shown that the LiF : F 2 - Q-switch has evident advantages over the YAG:Cr 4+ one in the senses of a much more expanded range of pump powers where the giant-pulse regime is supported in the laser and, as a consequence, potentially higher average output and peak pulse powers accessible. | eng_Latn | 7,853 |
Laser–diode-pumped passively Q-switched Nd3+:NaY(WO4)2 laser with GaAs saturable absorber | Abstract A laser–diode-pumped passively Q-switched new type crystal Nd 3+ :NaY(WO 4 ) 2 (known as Nd:NYW) laser with GaAs semiconductor saturable absorber has been realized. The dependence of pulse repetition rate, pulse energy, pulse width, and peak power on pump power for different output coupler reflectivities are measured. The coupled rate equations are used to simulate the Q-switched process of laser, and the numerical solutions agree with the experimental results. | We report the effect of removing a section of guiding layer from the propagation paths of ST-quartz Love wave sensors; this offers the ease of fabrication of a polymer guiding layer whilst retaining the native surface of the quartz which may then be used for the attachment of a sensitizing layer. Data is presented for rigid and viscous loading, which indicates a small reduction in mass sensitivity compared to a Love wave device. Biosensing capabilities of these discontinuous ‘sectional’ guiding layer devices are demonstrated using protein adsorption from solution. | eng_Latn | 7,854 |
SVM-Modified-FFE Enabled Chirp Management for 10G DML-Based 50Gb/s/λ PAM4 IM-DD PON | We propose a novel machine learning based equalization algorithm for bandwidth-limited IM-DD PON in C-band. 50Gb/s/λ. PAM4 transmission is demonstrated over 20km SSMF using a 10G-class transmitter with 21dB loss budget without amplification. | We report on a design and simulation of silicon on insulator apodized surface diffraction grating fiber to chip coupler by ::: sub-wavelength structure which is compatible with 193 nm laser DUV lithography. The structure of designed fiber to ::: chip coupler consists of two parts: a relatively large tapered segment and a segment with the surface diffraction grating ::: having sub-wavelength structure. The first segment adjusts cross-section of silicon on insulator wire single mode ::: waveguide to standard single mode fiber diameter and the second one is designed for vertical coupling to the fiber. Four ::: types of surface diffraction grating apodization by sub-wavelength structure are designed and simulated. The simulation ::: of the fiber-to-chip coupler is performed by FDTD simulation method. The simulation results of coupling effects for ::: each apodization of surface diffraction grating are evaluated and compared with each other. | kor_Hang | 7,855 |
Review of Progress in Photonic Band-Gap Fibers | The unique properties of air-core photonic band-gap fibers and their underlying principles of operation are reviewed. In addition, applications and other opportunities for these fibers are reviewed. Article not available. | Optical data transmission applications emerging from the Roadmaps; raising Telecom bandwidth efficiency, the role for PICs; microprocessor IO Bandwidth density and optical interposers; data center power reduction; optical backplanes; on-chip interconnect. | eng_Latn | 7,856 |
A novel GaP/InGaAs/InGaSb triple junction photovoltaic cell with optimized quantum efficiency | The third generation photovoltaic technology mandates high efficiency and low cost. Efficiency will increase when the absorber becomes capable of absorbing more photons, leading to formation of excitons in the absorber. The proposed GaP/InGaAs/InGaSb triple junction solar cell is designed to convert more incident photons to electricity, executing higher internal quantum efficiency (IQE), promoting higher efficiency solar cells. The use of InGaSb (0.54 eV) as a bottom subcell layer empowers the collection of photons deeper in infrared spectrum. This paper presents the result of QE vs. wavelength of each subcell layer. We optimized IQE vs. wavelength by varying different parameters like thicknesses and diffusion lengths to attain higher efficiency and making the solar cells more cost-effective. | There is no known simple rule that assures the existence of interface states in photonic crystals (PCs). We show here that one can control the existence or absence of interface states in 1D PCs through engineering the bulk geometrical phase such that interface states can be guaranteed in some or all photonic bandgaps. We verify experimentally the interface state design paradigm in 1D multilayered PCs fabricated by electron beam vapor deposition. We obtain the geometrical phases by measuring the reflection phases at the bandgaps of the PCs and achieve good agreement with the theory. Our approach could provide a platform for generating a PC interface state for various applications. | eng_Latn | 7,857 |
A Modification to a Flashlamp-Pumped Dye Laser to Increase Stability of the Spatial Mode | Abstract : It was determined by Fitzpatrick and Piepmeier that the spatial mode structure of the beam from a CMX-4 dye laser (Chromatix, Sunnyvale, CA) could be stabilized by maintaining a precise relationship between dye loop and cooling water loop temperatures. A passive modification to the laser is described that eliminates the active heating and cooling mechanisms that were employed by the initial investigators to accomplish this. | We present, to our knowledge for the first time, results of ultrasound-modulated light signals on living tissues. In particular, we analyze, both theoretically and experimentally, the effect of speckle fluctuations on the signal. We find that two different kinds of noise compete--shot noise and speckle noise--and are present at different levels in static phantoms and ex vivo tissue samples on the one hand and in dynamic phantoms and living tissues on the other hand. | eng_Latn | 7,858 |
Energy scaling of gas nonlinear optics | Nonlinear light-matter interactions, such as filamentation or high-order harmonic generation, are at the heart of nonlinear optics. Scaling of such effects is crucial to benefit optimally from novel laser developments. We introduce and discuss a general scaling model for nonlinear light-matter interactions in gases. | High efficiency of solar cells may be obtained at high concentration and narrow-band spectrum system. Difficulties are encountered in determination of the cell efficiency using narrow-band-artificial-light sources at high concentration. A method is proposed in this article for determination of the solar cell efficiency at high concentration and narrow-band spectrum. This method is based on measurement of the solar cell fill factor and the open-circuit voltage at moderate concentration and full spectrum, and based on a calculation procedure. | eng_Latn | 7,859 |
Organic Light Emitting Material and OLED Using The same | The present invention is a hole in the organic light emitting diode (OLED), a compound derivative and the organic light-emitting as a diode on, and more particularly, triphenylene preparing a compound derivative and this organic light-emitting of the formula (1) having a high glass transition temperature of the diode using the same that is used for using a transmitter to increase the life of the excellent thermal stability and the device, the light emission luminance and luminous efficiency to provide an excellent organic light emitting diode. Formula 1 (In the general formula (1), R1 or R2 must represent a substituted or unsubstituted aryl group having 6 to 14 nuclear carbon atom ring.) The organic light emitting, diode display device, a hole transport material, triphenylene | (57) Abstract: The present invention is basically relates module and a module housing (1) (10). The module housing (1), the photoelectric converter (5) installed by inserting the lead frame (3) and of the interior of the module housing (1), filled by casting compound of translucency. A plug socket (7) having a prescribed outer contour is formed on the outer housing wall. Optical waveguide component (6) is located inside the plug socket (7). The optical waveguide component, from the periphery of the outer surface of the plug socket (7), extends to the interior of the housing through the internal and housing opening of the plug socket (7), the photoelectric converter (5) optically It is coupled. Module optical waveguide plug (20) operating in conjunction with (10) has a sleeve-shaped plug portion matching the plug socket (7) (27). | eng_Latn | 7,860 |
Multiphoton cross-section measurements with low-power cw laser-induced luminescence. | A new method is presented that yields absolute multiphoton cross-section value gamma(n)(n = 2,3) by comparative one-, two-, and three-photon luminescence measurements and by utilizing low-power single-mode cw lasers. The experiments were performed on different dye solutions. The gamma(2) and gamma(3) experimental values obtained are compared with previous experimental data obtained with high-power laser sources. | Many conventional methods to detect propagation losses in optical waveguides, such as Cut-Back Method and Prism-Sliding Method, are either destructive or inconvenient. Here we demonstrated a new method -- CCD camera photographing method. A CCD camera was used to take digital photographs of the light streak in the waveguides and the scattered-light intensity distribution is recorded. After fitting the intensity distribution into an exponential attenuate curve, the propagation loss finally can be calculated from the attenuation coefficient of the curve. Compared with other detecting methods, it is more convenient and accurate. In our experiment, samples of polymer waveguides with propagation losses less than 0.5 dB/cm were fabricated. | eng_Latn | 7,861 |
Femtosecond transillumination tomography in thick tissues | We describe diffuse-light time-gated imaging with transillumination optical coherence tomography. Submillimeter-resolution imaging of objects hidden in thick biological tissue is achieved in cases in which ballistic light is absent by selecting only the early-arriving coherent portion of the diffuse transmitted light. By using a femtosecond laser as a high-power low-coherence light source, we perform high-sensitivity (130-dB dynamic range) optical gating with interferometric heterodyne detection. The dependence of image resolution on coherent photon arrival time is investigated in model scattering media. | A new approach of speech de-noising is put forward--second-decomposition wavelet global threshold.This ap-proach is different from the traditional methods.First,it decomposes high frequency twice,and then de-noises the signal by threshold de-noising.Simulated test is made on MATLAB.Test results show that the algorithm improved upon signal to noise ratio,and wiped off the most noise with full effective energy.At the same time,the interference problem of noise signal is absolutely solved. | eng_Latn | 7,862 |
Design of direct digital frequency synthesis based on FPGA and LabVIEW | A method to develop a DDS signal source with frequency controlled based on LabVIEW and FPGA is introduced.With the DDS,the function and structure of LabVIEW control panel and FPGA device are introduced.The output wave by test achieves the required aims and ensures the reliable and stabilization. | The authors report the realisation of a contradirectional EDFA whose 1480 nm pump beam, generated by a DFB laser diode, is recycled in it by a photoinduced intracore fibre bragg grating. Insertion of the fibre grating does not introduce any extra input coupling loss and, for the same gain and noise figure values, allows a 20% decrease of the pump power compared to the EDFA without a fibre grating. | eng_Latn | 7,863 |
Modelling of a self-sustained discharge-excited ArF excimer laser: the influence of photo-ionization and photodetachment by laser light on the discharge development | The effect of the laser light on the discharge development characteristics in the active medium of an ArF excimer laser is investigated using a one-dimensional fluid model including laser-light-induced photo-ionization and photodetachment processes. These processes are found to have a significant effect at times after the maximum in the laser output signal. For example, the laser-light-driven interactions increase the bulk electron number density by a factor of two and the electric field adjacent to the cathode by a factor of 1.5. Near the anode, the field changes from slightly negative at early times to extremely positive near the end of the laser pulse, resulting in electron drift in the direction of the bulk plasma. This tendency of the field to change sign at the anode is not observed when photon processes are neglected. This strong field enhancement suggests the generation of a filamental instability at the electrodes, as is indicated by experiments. | Summary form only given. There is a high demand for ultrastable, ultra-violet single-frequency pulses in a large number of applications. Two examples are writing fiber Bragg gratings and LIDAR systems. Both applications need high average output power. However, a very compact approach to obtain single-frequency UV pulses has been realized, but the average output power was low. Other similar laser systems lead to sufficiently high average output power, but suffer from low pulse to pulse stability. We report on a laser system that combines the advantages of both of the previous laser systems, single-frequency operation and high average output power. | eng_Latn | 7,864 |
Pulse Formation Dynamics in Giant Chirp Oscillators | We use numerical simulations to probe the pulse dynamics of mode-locked fiber lasers with extreme normal dispersion (as large as 21.5 ps2). Pulse formation and the support of dark solitons is described. | We propose a monitoring indicator of the normality of the output of a gravitational wave detector. This indicator is based on the estimation of the kurtosis (i.e., the 4th order statistical moment normalized by the variance squared) of the data selected in a time sliding window. We show how a low cost (because recursive) implementation of such estimation is possible and we illustrate the validity of the presented approach with a few examples using simulated random noises. | eng_Latn | 7,865 |
New compact high-specific-power slab gas lasers for medical and environmental studies | One of the most promising and easy-to-realize designs of gas laser with high specific output power and a small-size laser head involves a transverse RF discharge in a narrow gap between two wide, parallel electrodes(the slab configuration of discharge) and a hybrid waveguide-unstable resonator [1 II. Tn the present work we describe prototypes of smallsizc 3O and 5OW CO2 slab lasets with waveguide-unstable resonators, which can be considered as basic designs for industrial production. We investigated the output-power parameters of these lasers. Furthermore, we examined the spectral characteiistics of the lasers and the possibility of tuning the radiation wavelength in a wide range. The CW Ar-Xe laser with RF excitation is described. The applications possibilities of these lasers in medicine and remote sensing are discussed. | Abstract Neuron-specific enolase has been measured by a specific enzymoimmunoassays in serums from untreated patients with small-cell lung cancer (SCLC), other type of lung cancer or non-maligant respiratory diseases. The serum level of this marker was significantly higher in patients with SCLC than in any other groups and was correlated with stage of the disease. Moreover during the course of the disease, the serum NSE level reached the maximal value during chemotherrapy in patients with positive clinical response. | eng_Latn | 7,866 |
Optomechanical effects of two-level systems | Two-level systems are observed to affect quantum measurements with superconducting electromechanical systems via Kerr-like nonlinearity and excess phase noise. We propose a magnetic electromechanical coupling scheme as its solution. | Based on dual-rail spatial coding, in this article a self-programming optical logic concept is proposed. The self-programming is formulated by different coding of input images. Thus all 16 binary logic operations can be realized optically in parallel. Experimental results are demonstrated. | eng_Latn | 7,867 |
70 GHz arbitrary modulation of chirped laser pulses by means of acousto-optics. | We report the arbitrary modulation of chirped ultrashort laser pulses with a 70 GHz bandwidth. In the proof-of-principle experiment, modulation of Ti:sapphire laser emission was performed by the acousto-optic dispersive delay line, and the temporal pulse shape was measured with a picosecond streak camera. | Abstract Manchego cheese pieces were hit with an impact probe and the acoustic response was recorded, analyzed, and used to assess the textural characteristics of the cheese pieces. The textural parameters measured by traditional instrumental methods increased during ripening, although the pattern of the increase was different for different batches. For the 2 acoustic impact probes used in this study, a change in the frequency spectrum took place as cheese matured, increasing higher frequencies and the energy content. Multiple linear regression (MLR) and partial least square regression (PLSR), considering the acoustical variables extracted from the spectrum, allowed for a good estimation of cheese texture. The textural characteristics of the cheese surface and in particular the maximum force in compression experiments (R 2 >0.937 for MLR and R 2 >0.852 for PLSR) were accurately predicted by the acoustic method; however, the texture of the central layers of the cheese are poorly assessed (R 2 | eng_Latn | 7,868 |
A photonic-assisted transceiver with wavelength reuse for distributed UWB radar | A photonic-assisted transceiver with wavelength re use for distributed ultra-wideband (UWB) radar is proposed and demonstrated. The transceiver converts an input optical phase modulated signal into an optical UWB pulse train based on phase modulation to intensity modulation conversion using a fiber Bragg grating, and performs wavelength reuse by re- modulating the phase modulated optical signal via an intensity modulator . The transceiver is applied in a UWB ranging radar. A centimeter l evel accuracy is achieved. | A robust and smart protoporphyrin-based polymer nanoplatform, which is capable of successively recognizing the variation of biological signals and reacting with them in a dynamic mode, is successfully developed. It combines the chemotherapy and photodynamic therapy in a same system, leading to a high treatment outcome while a low adverse side effect of therapeutic agent. | eng_Latn | 7,869 |
The Airyscan Detector: Confocal Microscopy Evolution for the Neurosciences | First introduced in August 2014, the Airyscan detector from ZEISS represents a new detector concept for laser scanning microscopy (LSM) that enables a simultaneous resolution and signal-to-noise ratio (SNR) increase over traditional LSM imaging. The Airyscan detector innovation replaces the conventional LSM detector and pinhole scheme for an array of 32 sensitive GaAsP detector elements placed in the pinhole plane to generate an optical section. The new detection geometry allows for the collection of the spatial distribution of light originating from every point of a microscopic fluorescent object at the pinhole allowing access to higher frequency information and while additionally collecting more light for ultra-efficient imaging. In May 2015, the fast mode innovation for Airyscan combines illumination shaping with pinhole-plane imaging that enhances acquisition speeds by four times while simultaneously increasing SNR and resolution overcoming the traditional compromises of LSM imaging. | A wide field CCD camera has been developed for asteroid searches and has been used at our Schmidt telescope since September 1993. This paper describes this camera and its software as well as the changes it introduced in the type of programs that were requested on the telescope, and changes introduced in the way the telescope is operated. | eng_Latn | 7,870 |
Simple capacitive probe for high‐voltage nanosecond pulses | We describe a capacitive probe for the observation of high‐voltage fast pulses (1–100 kV, 1 to 10 ns) and we also show the results of some tests performed on a prototype. The probe is extremely simple and cheap, easy to build by small research groups. The attenuation factor can be adjusted through a simple operation which does not require substitution of components. | Recently large area avalanche photodiodes with high performance, narrow operation tolerances and high reliability became available. We report on some tests of their performance for the readout of fast scintillators. > | eng_Latn | 7,871 |
QoS-based Multi-domain Service Provisioning | This paper proposes an integrated solution, which based on probability routing, using multi-domain path selection, multi-domain path negotiation and intra-domain QoS-based routing algorithm, to provide multi-QoS based (such as bandwidth and hops) multi-domain circuit provision in a few minutes. This method has been used in the SFS for Shanghai Telecom. | -We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GHz have been generated. | eng_Latn | 7,872 |
Ohmic contacts produced by laser‐annealing Te‐implanted GaAs | We report the formation of Ohmic contacts to high‐dose (∼1016 cm−2) Te‐implanted n‐type GaAs annealed with a Q‐switched Nd : YAG laser. The annealing results in a Te concentration greater than 10 times the equilibrium solubility and the formation of free Ga at the surface. Ohmic contacts of specific contact resistance rc≃2×10−5 Ω cm2 were obtained by first removing the surface Ga by an HCl etch and then backsputtering to remove 50 A of GaAs, thereby exposing a surface of high Te concentration. | In this paper, an “L” detection is proposed to check PCB short circuit ,open circuit, raised detect and recessed detect in a Automatic Optic Inspection(AOI). This method were researched and simulated in MATLAB environment, the results showed that it can raise the efficiency and accuracy. | eng_Latn | 7,873 |
Transmembrane Kinases and Their Role in Entamoeba histolytica Pathogenesis | The transmembrane kinases (TMKs) of Entamoeba histolytica are a recently discovered family of cell-surface proteins that bear sequence similarity to the intermediate subunit of the Gal/GalNAc adherence lectin. The TMKs have been implicated in growth response to serum components as well as the phagocytosis of host cells and bacteria, processes that are critical to amebic pathogenesis during infection of the human host. Members of the TMK family appear to function variously as active kinases or pseudo-kinases depending on the structure of their intracellular domains and likely interact with intracellular signaling networks during signal transduction. | A new approach to the creation of a quantum cascade laser is suggested, which employs interband transitions in quantum wells with a coherent electron transport. The coherent electron transport is studied based on the simplest two-band Kane model, in which the interaction between states of the conduction and valence bands is described taking into account only states in the light hole subband of the valence band. | eng_Latn | 7,874 |
Spectral evolution and relaxation oscillations in dye lasers | Abstract The spectral dependence of intensity transients is studied in a multimode pulsed dye laser. It is shown by numerical integration that damping of relaxation oscillations varies as a function of frequency. This new result is discussed in relation to the conceot of spectro-temporal evolution previously introduced and recently applied to short pulse generation. | -We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GHz have been generated. | eng_Latn | 7,875 |
Temperature effects on the modulation response of an injection-locked InAs/InP Quantum-Dash laser | The impact of device temperature variations on the modulation response of an injection-locked Quantum-Dash laser is analyzed. Lower slave operating temperatures result in a large reduction in the undesirable pre-resonance dip in the modulation resp onse. | The thermodynamic aspects of the polymorphic phase transition from {\alpha}-indomethacin to {\gamma}-indomethacin are the fundamental key to find the most bioavailable phase of indomethacin. In the present work, varying the temperature and solvent permittivity changes the polymorphic transitions. Hence, the thermodynamic properties such as enthalpy, Gibbs free energy, and entropy of both indomethacin polymorphs are determined in terms of the solvent permittivity as functions of indomethacin's temperature in a vacuum, which are crucially related to the stability, spontaneity, and reversibility of the polymorphic transformation. | eng_Latn | 7,876 |
High speed drilling of thin silicon wafer by UV laser | Drilling rate of thin silicon wafer of 50µm was investigated as a function of diameter and fluence by using KrF excimer laser. The drilling rate at constant fluence increases rapidly with decreasing beam diameter below 20µm, reaching approximately up to 4µm/pulse at diameter of 7µm. Melt ejection is the predominant mechanism in drilling at beam diameters less than 30µm, and approximately 60% of laser energy remains in the silicon wafer. A simple formula giving drilling rate was derived as a function of diameter and fluence of laser beam, and agreed well with the experimental values in a wide range of diameter and fluence. Drilling rate of 7milion holes/s of 10µm in diameter for 50µm thick silicon wafer are estimated at laser power of 100W. | We present what is to our knowledge the most complete 1-D numerical analysis of the evolution and the propagation ::: dynamics of an ultrashort laser pulse in a Ti:Sapphire laser oscillator. This study confirms the dispersion ::: managed model of mode-locking, and emphasizes the role of the Kerr nonlinearity in generating mode-locked ::: spectra with a smooth and well-behaved spectral phase. A very good agreement with experimental measurements ::: of pulse energy, spectrum, and temporal width of extracavity compressed pulses is found. | eng_Latn | 7,877 |
Feature Article: Near-Field Optical Second Harmonic Scanning Microscopy: Application to Nonlinear Optical Polymers | This article gives a brief review of nonlinear optical imaging in both the far- field and near-field. In particular, we are interested in the use of nonlinear near- field scanning optical microscopy (NSOM) to characterize the morphology of the ordering of chromophores in nonlinear optical polymers. Topological images and nonlinear NSOM images are presented for a self-assembled nonlinear polymer and for a poled nonlinear polymer. In both cases, it is found that the nonlinear images are for the most part uncorrelated with the surface topology. | A novel solution for a synthesized microwave local oscillator suitable for high capacity digital radio systems using multilevel QAM is described. The synthesizer approach covering all radio channels of a given RF band is based on a mechanically and electronically tunable dielectric resonator oscillator phase locked with a wideband PLL to a low noise UHF SAW reference oscillator. Based on a detailed analysis of all noise contributions the PLL configuration is optimized, so that very low phase noise and low sensitivity to microphonics are achieved. | eng_Latn | 7,878 |
Channel Estimator and Aliasing Canceller for Equalizing and Decoding Non-Cyclic Prefixed Single-Carrier Block Transmission via MIMO-OFDM Modem | Without a cyclic prefix (CP), most single-carrier (SC) transmissions can not adopt frequency-domain equalizer (FDE) directly. This work utilizes frequency-domain channel estimator (FD-CE) and decision-feedback aliasing canceller (DF-AC) to produce single-FFT SC-FDE. In this way, non-CP single-carrier block transmission (SCBT) can be decoded using sphere decoder of MIMO-OFDM modems to support multimode and backward compatibility under an acceptable complexity in IEEE 802.11 very high throughput (VHT). An iV-point FFT is sufficient to measure channel frequency responses (CFR) from .L-sample preambles (L ≤ JV/2). And then, M-bit block codes (M ≤ L) are decodable over frequency domains with DF-AC's help. Simulations and measurements imply that this work can ensure adequate performance, even if there is no CP existed against the distortions of multipath propagation. | An apertureless near-field scanning optical microscope (a-NSOM) setup is described. Special ::: consideration is given to important system components. Surface plasmons are defined, as is their relationship to a- ::: NSOM and their interaction with the scanning probe tip. We used this set-up to measure a metal-dielectric-metal ::: (MDM) antenna integrated with a quantum cascade laser (QCL). The former is introduced and described. The role ::: of the atomic force microscope (AFM) in the experiment is laid out and explained. Finally, the lock-in amplifier is ::: explained. Next, the system setup is introduced and explained from the point of view of the light path taken by ::: light generated in the laser. Finally, results are given for the MDM single nanorod antenna and the coupled MDM ::: nanorod antenna. Simulation, topography, and NSOM images are shown. Lastly, several experimental issues are ::: discussed as well as other types of NSOM. | eng_Latn | 7,879 |
Line tunable visible and ultraviolet laser | A novel method of making a line tunable, visible and near ultraviolet, laser source is proposed and ::: demonstrated. It requires only a single laser and 2 nonlinear crystals. It can produce outputs with ::: wavelengths that cover much of the spectrum from 0.26 to 0.67 mm. | The mathematical representation of modulation coefficient and intrinsic phase delay of PZT fiber-optic phase modulator are given. To study the temperature character, this paper design two measure system with a Mach-Zehnder and a Sagnac interferometer and get the experimental result curve which show that both parameters are linear with temperature approximately in set temperature range. | eng_Latn | 7,880 |
Dispersion and damping of acoustic phonons in quantum dots | The paper examines a variety of mechanisms that can shift or broaden the frequencies of acoustic phonons in quantum dots. These mechanisms take on added significance in view of recent indications that a number of potential applications of quantum dots-including some approaches to quantum computing-may be limited by decoherence effects caused by acoustic-phonon interactions in quantum-dot systems. | With the development of all-optic network, the hotspot of the research is moving from the backbone network to the metropolitan network, and then to the access network. Much attention has been paid on reducing the cost in these networks. One approach is to adopt Ethernet passive optical network (EPON) architectures in an access network. In this paper a solution of EPON of Broadcasting/WDMA architecture is presented, which is based on several low-cost DWDM devices developed newly by authors, including the precise-wavelength DWDM-LD, DWDM demultipler with interleaver, DWDM receiver array, and dual-window broad-band coupler. | eng_Latn | 7,881 |
On the Infrared Absorption Spectra of Several Gases | The spectra of acetylene, ethylene, n-butane, n-hexane, n-octane, benzene, toluene, cumene, ethyl alcohol, ethyl ether, and sulphur dioxide were investigated with a grating of 1134 lines per cm in the region between 3 and 4 μ. The absorption curves are represented in figures. A table gives the wave-numbers of the maxima and selected wave-number differences. The individual lines of the bands are not revealed, but the envelopes are obtained. From the latter an attempt is made to state what branches are present in the bands. Attention is called to relations existing among the wave-number differences. | We present the design, fabrication, and characterization of an optical microsource, which comprises InAs/InP quantum wires embedded in a suspended microdisk. Comparison between photoluminescence measurements and theoretical analysis allows for a clear identification of the whispering gallery modes. cw room temperature lasing operation is demonstrated. | eng_Latn | 7,882 |
Lasing from autoionization resonance | Abstract We derive semiclassical equations for a single-mode laser operating between a bound state and an autoionizing resonance. We study its steady state properties, find intensity-dependent frequency pulling effects, bistability and, in a certain sense, inversion-less operation. | Abstract The possibility of the generation of a megagaus magnetic field in a plasma, creating at atom tunnel ionization in a high-power laser radiation field has been predicted. | eng_Latn | 7,883 |
Enhancement of optokinetic responses by lateral hypothalamic areas associated with attack in cats | Abstract Stimulation of lateral hypothalamic sites associated with predatory attack and known to modify trigeminal reflex systems enhanced efficiency of visual following over a wide range of target velocities. Furthermore, lateral hypothalamic stimulation reversed reflex habituation seen after continuous and after repeated optokinetic stimulation. These findings support the hypothesis that the lateral hypothalamus directs behavioral responses relevant to orienting to and capturing prey, at least in part, by regulation of reflex mechanisms in different sensory modalities. Possible neural substrates for the observed effects are discussed. | A theoretical analysis is made of the kinetics of electronic–vibrational relaxation of excimer molecules in the active medium of a KrF laser. Equations are derived to describe the dependence of the lasing quantum efficiency on the photon flux in the resonator, on the mechanism of formation of electronically excited molecules, and on the composition of the active gas mixture. | eng_Latn | 7,884 |
Taurine and GABA neurotransmitter receptors, a relationship with therapeutic potential? | ABSTRACTTaurine is a β-amino acid present in high concentrations in different areas of the mammalian central nervous system (CNS). It participates in different physiological processes such as osmor... | Abstract Electro-optic tuning of vacuum Rabi coupling is demonstrated on a very high quality semiconductor quantum microcavity structure with reflectivity linewidths at resonance of 0.9 and 1.1 meV. The variation in energy of the reflectivity peaks as a function of electric field is fitted very well by a transfer matrix reflectivity (TMR) model, using an experimental determination of exciton oscillator strength, and hence exciton-photon coupling strength, with electric field. In high sensitivity photo-current experiments we obtain clear evidence for coupling to discrete excited and continuum exciton states. | eng_Latn | 7,885 |
Pulse-periodic 600-W XeCl laser for industrial applications | The results are given of the construction of a high-power excimer laser capable of generating λ = 308-nm radiation with an average power of ~ 600 W. The laser power supply system was based on four commercial thyratrons and a magnetic switch. As an example of an application of such a laser, the results are given of the formation of a structure of apertures in polyimide deposited on aluminum. A binary film of this type serves as a flexible substrate used to mount large-scale integrated circuits. | Abstract The initial intensity of charge recombination luminescence (CRL) emitted by epoxy resins after brief periods of UV irradiation during cure has been measured for a number of resins as a function of cure time. The results are correlated with measurements of extent of reaction of the epoxy groups, using near-IR spectroscopy, and with rheological measurements. They show that the intensity of emission is directly related to the fractional conversion of the epoxy groups, irrespective of the cure temperature, but that the emission only occurs when the conversion is high enough for the resin to be glassy. Attempts to increase the emission by adding aromatic amines failed. It is proposed that, for CRL to be observed, the resin must contain enough OH groups to stabilise the electron traps by solvation and be vitreous enough to prevent immediate recombination of electron–cation pairs. | eng_Latn | 7,886 |
Recent progress in research of optoelectronic materials | It is well known that crystal growth is an essential area of research for optoelectronic materials. In the present paper the growth techniques and the advanced progress in development of crystal materials important for optoelectronic applications are described. New growth techniques, developed in the authors' laboratory, enabling the introduction of expanded applications of new materials are presented. After a review of recent developments of new techniques for optoelectronic materials, own experimental studies will be discussed. | Optical data transmission applications emerging from the Roadmaps; raising Telecom bandwidth efficiency, the role for PICs; microprocessor IO Bandwidth density and optical interposers; data center power reduction; optical backplanes; on-chip interconnect. | eng_Latn | 7,887 |
An active timing controlled-gate fluorescence lifetime imaging microscopy using an ultrafast picosecond diode laser | We report a time-gated fluorescence lifetime imaging microscopy (FLIM) using an active timing-controlled device and an ultrafast picosecond diode laser. This system could utilize more precise synchronization between laser excitation pulse and ICCD gate combining low timing-jitter diode laser with high precise timing control unit. Two flexible trigger signals for laser source and intensifier gate could adjust time sequence with picosecond precision compared with conventional passive delay adjustment. The importance of the adjustable repetition rate of this laser source is discussed with respect to noise reduction and precision in the lifetime determination, illustrating a further significant advantage over conventional mode-locked solid-state lasers. This FLIM system instrument could satisfy a wide temporal dynamic range demand for various biological applications. | Publisher Summary ::: Wave propagation in asymmetrically stacked composite laminate, because of high frequency impact loading, is studied using a new spectral finite element (SFE) formulation. This novel element is developed using matrix methodology similar to finite element (FE) formulation and has an exact dynamic stiffness matrix, obtained by exactly solving the governing Navier equation in the frequency-domain. As the mass distribution is modeled exactly, the element gives the exact frequency response of each layer. Thus, one element may be as large as one complete layer; and as a result, the system size is nominal compared to the conventional FE system sizes. The fast-Fourier transform (FFT) and Fourier series are used for inversion to the time/space domain. The element captures the essential wave propagation phenomena successfully and demonstrates Rayleigh wave in the surface and Stoneley wave in composite layer interfaces. | eng_Latn | 7,888 |
Principle and Realization of Paratactic Structure Brushless HESM | To solve the question that output voltage can not adjusting of the permanent magnet synchronous machine(PMSM),a kind of new type machine-the paratactic structure hybrid excitation synchronous machine(HESM) is introduced,its structure and working principle is described,and its equivalent magnetism circuit is analyzed,the non-load characteristic,load characteristic and regulative characteristic are tested. The result of test show: the paratactic structure hybrid excitation synchronous machine solved shortcoming of PMSM,the structure is feasible. | We present optically pumped lasing from group IV GeSn/SiGeSn heterostructures. A comparison between double heterostructure and multi-quantum-well microdisk cavities reveals advantages of the multi-well design. Strongly reduced lasing thresholds compared to values from bulk devices are observed. | eng_Latn | 7,889 |
Raman Response Induces Moving Cavity Solitons in Optical Resonators | Macroscopic systems are often subjected to time-delayed feedback. This effect is originated from temporal correlations that are inherent not only to optical and to magnetic systems, but also relevant to population dynamics where the birth rate includes the effect of maturation [1]. The delayed nonlocal response in nature is a rule rather than the exception. | In this paper, a Rotman lens with Ridge Gap Waveguide technology (RGW) is proposed as an alternative for beam scanning in millimeter wave applications. To facilitate the design and measurements, a first prototype at 38 GHz will be designed and built; afterwards a final device at 60 GHz will be designed. | eng_Latn | 7,890 |
Traffic Analysis Tools for Integrated Digital Time-Division Link Level Multiplexing of Synchronous and Asynchronous Message Streams | Information is transmitted over a digital link in repetitive time intervals called frames; each frame consists of one or more time slots. Theoretical performance limitations of a variety of time-division multiplexing policies for models of synchronous and asynchronous message streams are studied. | This paper reports on the development of optically based techniques to detect and identify chemical agents. Detection ::: sensitivity and molecule discrimination are studied. In parallel, efforts are made to develop rugged and compact ::: experimental designs that can be used for field measurements. Laser Induced breakdown spectroscopy (LIBS) is a ::: surface analyzing optical technique investigated to measure sarin like molecules deposited on samples coming from the ::: Parisian subway. On the other hand, Tunable Diode Laser Spectroscopy (TDLS) - Cavity Ring-Down Spectroscopy ::: (CRDS) or Cavity Enhanced Absorption Spectroscopy (CEAS) - is used to measure traces of the industrial toxic ::: hydrogen fluoride gas down to the ppb level. Measurements in laboratory are reported and primary results obtained in a ::: field experiment are described. | eng_Latn | 7,891 |
Implantation of Organic Molecules into Biotissue by Pulsed Laser Irradiation | Zinc tetraphenyl porphyrin (ZnTPP) molecules were implanted into a piece of chicken skin by irradiation with KrF laser pulses. The study of the implanted ZnTPP at the skin surface using a fluorescence microscope indicated that the molecules are space-selectively introduced at the irradiated area. | We present optically pumped lasing from group IV GeSn/SiGeSn heterostructures. A comparison between double heterostructure and multi-quantum-well microdisk cavities reveals advantages of the multi-well design. Strongly reduced lasing thresholds compared to values from bulk devices are observed. | eng_Latn | 7,892 |
Interferometric wavelength converter operating at 10 Gb/s based on a monolithic-integrated photonic circuit | Abstract In this work we present a wavelength converter based on a Michelson interferometer. It is obtained by monolithic integration of two-semiconductor optical amplifiers with a passive waveguided X-coupler, incorporating turning mirrors. It operates in the 1.55 μm spectral window and allows the wavelength conversion of data streams up to 10 Gb/s, showing open-eye diagrams and extinction–ratio regeneration capabilities. Comparison of two structures with different active layers and their influence on the polarization sensitivity is also presented. | A new process for separating high quality single‐crystal InP thin films from the growth substrate is reported. These thin films were used for transmission measurements to determine InP absorption coefficients above the band edge. Photoluminescence measurements performed on these films before and after the fabrication process verified that the high quality of the separated thin film was not affected by the fabrication process. Two n‐type InP thin films, one with a doping concentration of 1.4×1017 cm−3 (1 μm thick) and the other with a doping concentration of 3.2×1018 cm−3 (2.5 μm thick), were grown and subsequently separated from the substrate. Using these separated films, the first direct transmission measurements of above band edge absorption coefficients in doped InP films are reported in this letter. | eng_Latn | 7,893 |
Full Characterization of Low-Power Picosecond Pulses From a Gain-Switched Diode Laser Using Electrooptic Modulation-Based Linear FROG | We use a linear frequency-resolved optical gating technique based on electrooptic modulation to fully characterize for the first time the highly chirped pulses from a 1.06-m Fabry-Perot laser diode and design a chirped fiber Bragg grating to provide high-quality pulse compression. With this grating, we achieved 18-ps pulses at a repetition rate of 1.35 GHz with a time-bandwidth product of 0.7. | The traditional PID control inverter power supply system could not fundamentally solve the conflict between dynamic quality and stable precision,so a new fuzzy-PID control scheme was proposed,which combined the advantages of fuzzy control and the PID control and could adjust the PID parameter in real-time with DSP control chip.The simulation results show that this control scheme can improve the dynamic quality and the system steady precision. | eng_Latn | 7,894 |
An in vivo photodynamic therapy with diode laser to cell activation of kidney dysfunction | This study aims to analyze the effect of photodynamic therapy (PDT) low level laser therapy (LLLT) 650 nm in the experimental animals mice (Musmuculus) suffering from kidney organ damage in mice (Musmuculus) in vivo. Exposure laser acupuncture was performed on the kidney BL-23. The conditioning of kidney damage in mice used carbofuraan 35 at a dose of 0.041697 mg/mice. LLLT 650 nm exposure was done on a wide variety of energy (0.5; 1.0; 1.5; 2.0; 4.0; 5.0; 6.0; 7.0) J. The histopathological kidney cells in mice renal impairment showed that exposure to 650 nm laser energy 1 Joule resulted in the reduction of damaged cells (necrosis) and normal cells were increased with the improvement of renal tubular cells (64.14 ± 8:02)%. Therefore, exposure to 650 nm LLLT on acupuncture points Shenshu (BL-23) has the ability to proliferation of renal tubular cells of mice. | With the development of all-optic network, the hotspot of the research is moving from the backbone network to the metropolitan network, and then to the access network. Much attention has been paid on reducing the cost in these networks. One approach is to adopt Ethernet passive optical network (EPON) architectures in an access network. In this paper a solution of EPON of Broadcasting/WDMA architecture is presented, which is based on several low-cost DWDM devices developed newly by authors, including the precise-wavelength DWDM-LD, DWDM demultipler with interleaver, DWDM receiver array, and dual-window broad-band coupler. | eng_Latn | 7,895 |
Analysis of germanium-doped silicon vertical PN junction optical phase shifter | In this paper, the performance of a germanium-doped silicon optical phase shifter with vertical PN junction has been investigated. The proposed phase shifter is simulated using a process simulation tool, and 2D carrier distribution has been used to calculate the phase shifter performance metrics. The designed phase shifter is integrated into a Mach–Zehnder interferometer structure, and the transfer characteristics are plotted. The proposed phase shifter has a phase shift of ∼141°/mm, VπLπ of ∼0.64 V·cm, insertion loss of ∼1.23 dB, and 3 dB bandwidth of ∼37 GHz at 5 V reverse bias. | We present first-principles studies on how to engineer band lineups of nanosized radial heterojunctions, Si/Ge core-shell nanowires. Our calculation reveals that band offsets of these one-dimensional nanostructures can be tailored by applying the axial strain. In particular, the valence band offset can be efficiently tuned in a wide range and even be diminished with applied strain. Two mechanisms contributing to this strain engineering of band offsets are discussed. Our proposed approach to control band offsets in nanosized heterojunctions may be of practical interest for nanoelectronics and photovoltaic applications. | eng_Latn | 7,896 |
Analysis of self-oscillating switched-mode circuit for low-voltage energy harvesting | The operation of a self-oscillating switched-mode circuit topology for low-voltage thermal energy harvesting is analysed and experimental efficiency results are presented. Circuit self-start-up function as well as high-efficiency power transfer are obtained by using only one transformer without additional inductors. It is shown that even without using a maximum power point tracking (MPPT) tracking circuit, it is possible to achieve efficiencies up to 65% over a relatively broad input voltage range which can be optimised by properly varying the transformer turns ratio n. | Abstract This paper describes the design and principle behind the demonstrated novel lamellar grating out-of-plane gyroscope design. The sensing mechanism is based on out-of-plane motion of movable light-reflecting beams changing the phase relationship between the light reflected off the two sets of beams. This phase relationship is manifested as an intensity change in the zeroth-order diffracted light. The device consists of two in-plane 180° out-of-phase vibrating masses with a set of overlapping light-reflecting beams behaving essentially as a lamellar grating. The commercial SOI-MUMPS process was used to fabricate a prototype. The gyroscope demonstrated a sensitivity of 17.8 μV/(°/s) and linearity error of less than 0.6%. Design issues were addressed and show promise to be overcome. Post-fabrication tuning and better optics design can improve the performance greatly with respect to the current prototype setup. | eng_Latn | 7,897 |
Stereo image format converter and method and stereo image format conversion method | The invention discloses a stereo image format converter and method therefor. The stereo image format converter includes an input circuit, a processing circuit and an output circuit. The input circuit receives a frame-encapsulation signal which includes an image signal, a first vertical synchronizing signal and a first data-enable signal. According to the frame-encapsulation signal, the processing circuit determines an active space of the image signal, then processes the first vertical synchronizing signal to generate a second vertical synchronizing signal and processes the first data-enable signal to generate a second data-enable signal. The processing circuit generates a frame-continuous signal which includes the image signal, the second vertical synchronizing signal and the second data-enable signal. The output circuit outputs the frame-continuous signal. | Long-wavelength identification of microcalcifications in breast cancer tissue is demonstrated using a novel upconversion raster scanning microscope. The system consists of quantum cascade lasers (QCL) for illumination and an upconversion system for efficient, high-speed detection using a silicon detector. Absorbance spectra and images of regions of ductal carcinoma in situ (DCIS) from the breast have been acquired using both upconversion and Fourier-transform infrared (FTIR) systems. The spectral images are compared and good agreement is found between the upconversion and the FTIR systems. | eng_Latn | 7,898 |
Accessory to the cathode ray oscillograph for changing oscillograms from a sinusoidal to a linear time base | An instrument is described which will convert an oscillogram, taken with a cathode ray oscillograph and using a sinusoidal reference deflecting field, into an oscillogram having a linear time base. | -We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GHz have been generated. | eng_Latn | 7,899 |
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