用微光学技术制作位相型聚焦光栅

根据菲涅耳衍射理论,采用微光学制作技术通过3次套刻,将8位相台阶的菲涅耳波带片和平面光栅组合制作在同一块基片上,构成同时具有色散分光和聚焦光谱线功能的位相型光栅.这种光栅具有较高的光谱分辨本领和衍射效率,而且光路简单,调节方便.实验测出的衍射效率大于71%.     

强激光辐照光电探测器的研究

本文报导强激光辐照光电探测器所产生的各种效应、典型的实验和理论分析方法，对在实验中发现但未及解决的问题也作了介绍。     

光电探测器激光损伤热模型分析

本文在考虑了激光在材料内的热源效应后,求解了热扩散方程,给出了三种情况下激光破坏阈值与脉宽的关系式。借助材料表面的温度分布曲线,讨论了材料破坏的热机理。用这一模型可预测材料的破坏阈值,验证数值计算的结果;在已知某一脉宽的破坏阈值求另一脉宽下的阈值时也是有效的。最后比较了实验结果与理论预测值,它们在一定范围内符合得很好。     

光电探测器的激光破坏机理研究

本文主要分析激光辐射各种光电探测器及其相似材料结构时，所产生各种破坏效应的物理机制，进而分析讨论产生各种破坏效应时的理论计算模型及其适用性。最后探讨光电探测器及其相似材料的激光破坏机理相关研究的发展方向。     

激光干扰远场光电探测器能量估算方法

为了研究复杂电磁环境下激光武器对抗光电精确制导武器的关键技术,综合分析了激光大气传输、大气湍流效应、探测器自身因素、激光干扰系统瞄准精度等因素对激光干扰效果的影响.以CO2激光辐照红外成像制导武器为例,研究了激光在大气中的传输特性,建立了激光有效干扰远场光电探测器时所需激光能量的估算模型,总结了形成有效干扰所需激光能量估算的一般方法,丰富了激光与光电探测器相互作用的研究,对提高复杂电磁环境下的光电对抗能力具有重要意义.     

强激光对光电探测器的损伤机理研究

详细讨论了强激光对光电探测器的损伤类型，并初步讨论了损伤机理。提出了一种测定光电探测器损伤的实验方法。     

激光与PIN光电探测器相互作用的响应度研究

通过比较短路电流的方法,标定了探测器对He-Ne激光的响应度。用Nd∶YAG激光辐照PIN光电探测器,通过测量激光辐照后探测器对He-Ne激光的短路电流,获得了探测器响应度变化与辐照激光功率密度的关系。从实验数据可知,探测器被功率密度低于7.6×105 W/cm2的Nd∶YAG激光辐照后,不会发生损伤,激光辐照后,探测器对He-Ne激光的响应度不发生改变;当Nd∶YAG激光的功率密度超过9.6×105 W/cm2时,激光辐照后,探测器对He-Ne激光辐照的响应度开始下降,PN结遭到破坏是探测器响应度下降的根本原因,扫描电镜的结果与我们的分析相一致。     

红外激光辐照下光电探测器光谱响应度的研究

响应度R是反映探测器性能的一项重要指标.当光电探测器被激光损伤后,其响应度R将会下降.文中探讨了强激光对光电探测器的损伤机理,对不同功率密度强激光作用下探测器的光谱进行了测量,研究了探测器在强激光辐照下探测器响应度变化规律.对光电对抗以及光电探测器的抗激光损伤研究具有一定的参考价值.     

超高速光电探测器

现代激光科学研究、核爆模拟、惯性约束核聚变（ICF）研究等领域需要测量半宽度100ps左右的超高速激光脉冲。超高速光电探测器就是探测光信号并转换成相应电脉冲的有力工具。     

激光对光电探测器的损伤阈值研究

本文研究了1.06μm和0.53μm激光对硅pin光电二极管以及硅雪崩光电管的永久性损伤效应,测出了损伤阈值。实验发现,光电探测器的PN结受到激光热烧伤是造成其永久性损伤的重要因素,损伤阈值的大小与激光波长、脉冲宽度以及光电探测器结构有关。     

Impulse responses of submicron GaAs photodetectors

Metal–semiconductor–metal photodetectors with different submicron spacings (d = 100, 300, 500, 700 and 900 nm) were fabricated on GaAs with a carrier recombination time of 100 ps by electron beam lithography. Temporal responses of the detectors were measured by photoconductive sampling in order to identify factors which limits the response speeds. At a low excitation of <100 μW, the response speeds of 100, 300 and 500 nm spacing detectors are limited by parasitic capacitances of the submicron structures. The speeds of 700 and 900 nm spacing detectors are limited by an electron/hole transport in the semiconductor. At a high excitation of >100 μW, the response speeds of the all spacing detectors are limited by field screening caused by electron–hole plasma.     

Improved optical heterodyne methods for measuring frequency responses of photodetectors

An improved optical self-heterodyne method utilizing a distributed Bragg reflector (DBR) tunable laser and an optical fiber ring interferometer is presented in this paper. The interference efficiency can be increased by 7 dB compared with the scheme using the conventional Mach-Zehnder interferometer. The unsteady process that the beating frequency experiences in each tuning period is investigated. According to the measurement results, the wavelength and optical power of the tunable laser will be steady when the square-wave frequency is lower than 300 kHz. It has been shown that when a square-wave voltage is applied to the phase section of the tunable laser, the laser linewidths vary in a wide range, and are much larger than that under dc voltage tuning. The errors caused by the variations in the linewidth of the beat signal and optical power can be eliminated using the proposed calibration procedures, and the measurement accuracy can, therefore, be significantly improved. Experiments show that the frequency responses obtained using our method agree well with the data provided by the manufacturer, and the improved optical self-heterodyne method is as accurate as the intensity noise technique.     

Theoretical analysis of the influences of barrier-enhancementlayers on transient responses of MSM photodetectors

Transient responses of In_0.53Ga_0.47As MSM PDs with abrupt and graded barrier-enhancement layers are simulated by using an ensemble Monte Carlo technique. The effect of the graded layer on transient responses and an appropriate graded-layer thickness for achieving fast responses are discussed. Also, a relevant device scaling law is proposed for In_0.53Ga_0.,₄₇As MSM PDs with graded barrier-enhancement layers     

新型光电探测器的研究

针对RCE光电探测器存在的问题提出两种解决方案。将InP／空气隙的分布布拉格反射镜(DBR)结构引入RCE光探测器,只用1．5对InP／空气隙计算反射率约为95％,解决了长波长反射镜制备问题。所制备的器件,在波长1．585μm处获得了约54．5％的峰值量子效率,以及8GHz的3dB响应带宽。另一种引入斜镜结构解除了量子效率与超窄光谱响应线宽的相互制约。     

Inline quantum-well waveguide photodetectors for the measurement ofwavelength shifts

A two-segment GaAs-InGaP-InGaAs p-i-n quantum-well waveguide photodiode has been fabricated and demonstrated to function as a sensitive wavelength monitor. The ratio of the two segments' photocurrents varies linearly with wavelength in a region near the absorption band edge. A wavelength sensitivity on the order of 1 pm was measured for input optical power levels above 30 μW and signal averaging times of 0.2 s. An operating range from 980 to 1020 nm was achieved using electroabsorption tuning of the band edge. The intended application for this detector is wavelength demodulation of Bragg grating fiber optic strain sensors. A strain sensor with resolution of ±6 μϵ was demonstrated using a superluminescent diode and the inline detectors to monitor strain-induced changes in the reflection wavelength of an in-fiber grating     

Refined model for the current-voltage characteristics of quantum-well infrared photodetectors

The temperature dependences of the dark current of quantum-well infrared photodetectors are investigated experimentally. It is established that the pre-exponential factor in the analytical expression for the photodetector current-voltage characteristics varies linearly with temperature. On the basis of the results obtained, it is suggested that the temperature dependence of the photodetector??s dark current is determined by the thermal excitation of charge carriers to a band characterized by a two-dimensional density of states. In the context of this suggestion, a refined model for the current-voltage characteristics is proposed. The model takes into account the thermal generation of charge carriers in a band with a two-dimensional density of states and the electric field dependence of the thermal activation energy for the quantum-well ground state and of the drift velocity of the carriers in the barrier conduction band.     

锗近红外光电探测器制备工艺研究进展

Ge材料由于在近红外波段具有较大的吸收系数、高的载流子迁移率、以及与Si工艺相兼容等优势而被视为制备近红外光电探测器最理想的材料之一。针对Ge光电探测器制备过程中面临的挑战,文中综述了近年来笔者所在的课题组在Ge探测器材料、器件及工艺方面的研究进展。首先介绍了Si基Ge材料的制备工艺,利用低温缓冲层生长技术、Ge/Si键合技术、Ge浓缩技术等分别制备得到高晶体质量的Si基Ge材料。研究了Ge材料n型掺杂工艺,利用离子注入结合两步退火处理（低温预退火和激光退火）以及利用固态磷旋涂工艺等分别实现Ge材料n型高掺浅结制备。最后探究了金属/Ge接触势垒高度的调制方法,结合金属中间层和透明导电电极ITO制备得到性能良好的Ge肖特基光电探测器。     

Integrated arrays of silicon photodetectors for image sensing

Development of linear and area arrays of silicon photodetectors operating in a photon flux integration mode is described. This mode of operation, which permits the trade of gain for bandwidth, is reviewed. It is possible to obtain full frame storage at commercial TV frame rates from area arrays of silicon phototransistors. Practical integrated structures of both diode and transistor arrays will be shown, and a method of coincidence sampling of an area array of photodetectors, which eliminates the need for isolation by the use of integrated MOST AND gates in the detector array, is described. This structure provides the following advantages: 1) High sensitivity and broad spectral response--photons absorbed far below the surface are not lost because of isolation barriers. 2) Reduced cross modulation. 3) A single video output terminal is required, thus avoiding the need to switch externally a large number of video channels to a common load, as is the case where isolation of photoelements is employed.     

Improved error correction technique for on-wafer lightwavemeasurements of photodetectors

An accurate correction technique for on-wafer small-signal lightwave measurements of photodetectors is presented. This technique is an improvement of the conventional calibration methods for on-wafer lightwave measurements. Mathematical expressions for the dominant error sources that exist in the measurement system are derived. Experimental results for an InGaAs-InP pin photodiode show a smoother modulation response characteristic when the presented technique is used     

Theoretical study of the response of InGaAsmetal-semiconductor-metal photodetectors

We present a theoretical investigation of the response of metal-semiconductor-metal (MSM) photodetectors made of InGaAs lattice-matched to InP using a two-dimensional drift-diffusion model with a thermionic-field emission boundary condition for the heterojunctions. The effect of including a top InAlAs layer to increase the effective barrier height of the metal fingers on the InGaAs active layer is thoroughly examined and found to limit the collection of the photocurrent signal due to the electron and hole barriers that it forms with InGaAs. Due to the thickness and height of the InAlAs barrier layer in existing designs, the tunneling current obtained from the model is found to be negligibly small to significantly affect the output signal current. In an attempt to obtain a better response, different design structures including one where a quasi-Schottky contact is utilized are studied and their speed of response, breakdown voltage, and dark current are compared to that of the usual InGaAs device