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本文对双区共腔半导体双稳态激光器在电注入下的稳态及瞬态特性进行了计算机模拟,这种模型产生双稳和自脉动现象的机制是不均匀电注入本征可饱和吸收特性,我们研究了与可饱和吸收有关的几个参数r、ξ、J_1、J_2对双稳及自脉动现象的影响. 相似文献
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通过速率方程建立外光注入半导体激光器的理论模型,在注入锁定条件下对其进行稳态及小信号分析,研究了注入光对调制特性的影响.结果表明,强光注入在一定程度上增大了谐振频率和调制带宽,但是抑制了响应增益,通过增大偏置电流加以补偿,才能获得理想的响应增益和带宽;并且外光注入大大降低了低频调制时的频率啁啾. 相似文献
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共腔双区(CCTS)DH激光器的研究 总被引:1,自引:0,他引:1
本文综合报导对AIGaAs/GaAs、InGaAsP/InP共腔双区(CCTS)DH激光器的研究,结果表明CCTS激光器具有稳态和瞬态多功能特性,作为三端器件通过工作状态的选择可以控制激光器的“开”,“关”动作,和改善输出线性度,还可以控制产生微波调制光脉冲序列,尤其是具有模式稳定的光输出双稳态特性。文中对上述现象作了物理解释和半定量的理论分析。 相似文献
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单腔双接触结构激光器双稳特性研究 总被引:2,自引:1,他引:1
本文从多纵模速率方程出发,在取定考虑有K选择的抛物带间吸收,增益系数的基础上,采用数值方法,对单腔双接触结构激光器的双稳特性的产生机理,以及影响它的两个最主要参数(即双稳区注入宽度和开关时间)的各种因素作了系统的分析. 稳态分析结果表明多纵模的工作状态将使双稳区注入宽度减少,而减少吸收区电注入或增大吸收区体积等可使双稳区注入宽度增大.瞬态分析结果表明,双稳开关过程可分为两个阶段,第一阶段谱宽大并伴有大幅度跳模;第二阶段占时较长,对双稳开关时间有较大影响,可通过加大增益区电注入来减少振荡衰减时间. 本工作为设计双稳器件,提高器件性能提供了基础. 相似文献
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The authors present a simple configuration of a gain-clamped semiconductor optical amplifier (GC-SOA) based on automatic intensity control of a feedback light generated by amplified spontaneous emission, using a narrow bandwidth thin-film-tunable filter. Experimental results show that the proposed amplifier has good gain clamping characteristics and the feedback light dramatically reduces steady and transient gain variations. The feedback light operates satisfactorily with the channel's add-drop frequency up to 20.9 kHz. We also examined the performance of the GC-SOA by employing the feedback light at different wavelengths. 相似文献
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Three-terminal three-color n-SiC:H/a-Si:H-based TCO/PINIP/TCO/PIN/metal detectors are presented. Assemblies having different surface roughness of transparent conducting oxide (TCO) layers are compared with regard to the external steady-state characteristics and transient behavior. The roughness of the sputtered TCO surface can be modified by an etching treatment. With the selection of smooth or textured TCO surfaces, the wave propagation of light within the device is controlled. This design technique can be exploited to optimize the color separation and improve the reproducibility of spectral responsivities in the assemblies. The examined assemblies exhibit very selective spectral responsivity for the fundamental chromatic components (red-green-blue) and a linear photocurrent-generation rate relationship over more than five orders of magnitude of illumination intensity. Since the color detection of blue and green light is performed in the PINIP structure by bias switching, the transient current response of the PINIP structures is investigated. A reciprocal relationship between the delay time and illumination intensity is established. An optimum operation region for the switching voltages is determined with regard to the quality of color separation, dynamic range, and transient behavior 相似文献
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Sa Cai Chaolei Zuo Jiayu Zhang Hui Liu Xiaosheng Fang 《Advanced functional materials》2021,31(20):2100026
Photodetectors, which convert the light signal into other forms of signal, have been under the spotlight of research for many years because they are widely applied in monitoring, communication, and imaging. Most of the currently available photodetectors can output electrical signals to indicate the transient light intensity, while some display color change to reveal the absorbed light dosage. However, there is no device that can tell the transient light intensity and accumulated light dosage at the same time. Here, a paper-based wearable photodetector that can simultaneously measure transient light intensity and accumulated light dosage is reported. The phosphomolybdic acid/citric acid system, whose color change can be observed by the naked eye, is designed as the photochromic material to combine with photodetective materials (using 2D Sr2Nb3O10 and ZnO nanoparticle as examples) on paper. Such paper-based photodetector fully utilizes natural hygroscopicity and softness of paper, showing decent flexibility. Its optoelectronic signal remains stable even after 1000 cycles of bending. To the best of one's knowledge, this is the first photodetector that can tell light intensity and dosage simultaneously. This work introduces a new type of wearable photodetector by structure design and material selection, shedding light on more novel works for convenient and practical photodetection. 相似文献
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介绍了一种用于粒子图像速度分析(PIV)的光源装置。利用该装置可在间得到一组相互平行的“光切面”,用于精确、快速地对复杂流场分布进行分析。 相似文献
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Jian Ping Wang Jin Ru Li Pei De Tao Xing Chang Li Long Jiang 《Advanced functional materials》1994,4(3):219-224
Langmuir–Blodgett (LB) films of bacteriorhodopsin (bR) without addition of lipids were deposited on indium tin oxide (ITO) conductive electrodes. A sandwich photocell with a juction structure of ITO/bR/electrolyte/ITO has been constructed in which the bR LB film was put into contact directly with an aqueous electrolyte immobilized in an agar gel. Under visible light irradiation a transient photocurrent due to a change in light intensity can be observedl showing the property of vision-imitative material. It can be used as a multiple optical switch, since it gives positive and negative transient photocurrnts during application and removal of light irradiation respectively and has a photoresponse repeatedly in the same direction when the light intensity increases or decreases stepwise. A photoalarm consisting of the bR photocell and an amplifier was set up by utilizing the switching function of the bR LB film. 相似文献
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Okuda M. Kan Y. Ohnishi T. Yamanishi M. Mukaiyama K. Otsuka N. Nakamura Y. Suemune I. 《Quantum Electronics, IEEE Journal of》1990,26(9):1481-1491
Extended experimental results on three-terminal quantum-confined field-effect light emitters with current injection and field control of luminescent characteristics in the quantum-well structure are reported. By incorporating superlattice buffer layers (SLBLs), the quantum efficiency of the device is dramatically improved and equivalently nonradiative recombination processes are sufficiently suppressed at room temperature. The red-shift of the emission spectra by the quantum-confined Stark effect assures that the electric field is effectively applied to the quantum well. The experimental data on the transient responses of emission intensity to input voltage pulses show fairly good correspondences with theoretical prediction and previous photoluminescence experiments. The authors discuss the ultimate capability of high-speed switching and point that an optical pulse with a duration as short as 30 ps and involving more than 100 photons can be generated by scaling down the size of the device with 1% external efficiency 相似文献
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We explore the transient characteristics of an interband resonant light modulation process by ultrashort intersubband resonant light pulses in semiconductor quantum wells (QW's). The modulation characteristics in a three-level semiconductor QW system, including the effects due to in-plane momentum, have been investigated by a numerical analysis of the coupled Bloch equations using a density-matrix approach. We have studied the effect of the carrier density and the nature of the intersubband coupling light on the transient absorption features of the interband light. The modulation process has been compared in doped and undoped QW's. The switching behavior of the strong interband light field in presence of a train of intersubband light pulses has also been discussed 相似文献
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Transient grating measurements on sample with an anisotropy or with multiple excited states are described. The general formula for the intensity of the diffracted light from a transient grating in a sample with an anisotropic diffusion coefficient is presented and is applied to CdS. A transient grating spectroscopic technique for a sample with multiple excited states is discussed in detail. In addition to these, the contribution of a population and a thermal grating to the observed signals is discussed. 相似文献
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The dynamic response of an organic bulk heterojunction photodiode to small changes in applied bias or light intensity is investigated as function of the intensity of a constant background illumination by means of photoimpedance and transient photocurrent measurements. For bias voltages close to the open circuit voltage we find that the response timescale with the square root of the light intensity. The results can be quantitatively explained in terms of a space charge limitation on the photocurrent as predicted by Goodman and Rose (J. Appl. Phys. 42, 2823 (1971)). The relaxation time of the diode at open circuit corresponds to the lifetime of the slowest charge carrier in the diode. This relaxation time is determined by the dielectric constant and the smallest of the two carrier mobilities in the bulk heterojunction. This illustrates the importance of balanced carrier mobilities for obtaining diodes with fast response time at low bias for e.g. imaging arrays. 相似文献
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针对助航灯具的发光特性,提出了一种测试助航灯具出射光强分布的方法。使用线阵CCD作为光电传感器,采集、获取各个方向灯具的光强信号,利用A/D芯片和USB接口芯片实现数据的转化和实时传输。通过改进的Delaunay三角剖分线算法和B样条曲线平滑处理算法的结合,提出了一种快速生成等光强曲线的算法,给出了Matlab软件获得等光强曲线的方法。通过对PAPI灯出射光强的测试及其等光强曲线的拟合,验证了该测试装置可以较好地实现光强测试,所提算法绘制的曲线平滑、速度快。 相似文献