在氙灯放电泵浦过程中, 片状放大器片腔内材料在高强度氙灯光辐照下, 存在显著的热解过程, 产生大量的μm级悬浮粒子。针对放大器在线洁净度控制，采取了包括选用有利于洁净控制的材料、消除盲孔与焊缝、深度酸洗刻蚀、高压喷淋清洗和最终的光照清洗等系列有效措施。实验研究结果表明：经过100发次光照清洗，片腔内气溶胶颗粒处于300～1000之间，接近美国国家点火装置(NIF)洁净水平；发次运行完成后，利用约0.4 m/s的氮氧混合气体对放大器腔体进行吹扫，气溶胶颗粒在2 min内可恢复至0值。

等离子体电极普克尔盒被广泛应用于大型激光驱动器中，用于抑制自激振荡、实现多程放大控制和反激光隔离，普克尔盒内的放电电极在长期使用过程中与腔内残余O₂发生反应出现退化现象，导致稳定性下降，寿命降低。为此，提出了封离型等离子体电极普克尔盒，其放电腔内的Ne气浓度可达99.9%，漏率小于1.0×10⁻¹⁰ Pa∙m³∙s⁻¹，理论使用年限大于40年。实验表明，封离型等离子体电极普克尔盒在工作20万发次后，其放电电极依然光亮如新，时间抖动仍稳定在6.4 ns附近，稳定性有了大幅提升。

Linearity is a very important parameter to measure the performance of avalanche photodiodes (APDs) under high input optical power. In this paper, the influence of the absorption layer on the linearity of APDs is carefully studied by using bandgap engineering with the structure model of separated absorption, grading, charge, multiplication, charge, and transit (SAGCMCT). The simulated results show that in the hybrid absorption layer device structure the 1 dB compression point can be improved from -9dBm to -2.1dBm by increasing the proportion of the p-type absorption layer. In the device structure with only one absorption layer, increasing the doping level of the absorption layer can also improve the 1 dB compression point from -8.6dBm to 1.43 dBm at a gain of 10. Therefore, the absorption layer is very critical for the linearity of APDs.

基于蒙特卡洛模拟方法，建立了一个水中激光偏振辐射传输模型，用于模拟分析船载偏振激光雷达水体垂直剖面的偏振探测回波，分析了不同光学参数的水体和激光雷达测量模式下的偏振测量误差。使用高斯分布设置了三种深度分布在10~30 m的低、中、高浓度散射层，其叶绿素a峰值浓度分别为0.1 mg/m³、1 mg/m³和10 mg/m³。模拟了激光发射波长为532 nm，接收视场角为10~1000 mrad的船载海洋激光雷达的偏振回波信号，并分析了影响偏振测量误差的主要因素。研究结果表明，由于激光在水中的多次散射过程，随着探测深度、叶绿素a浓度和接收视场角的增大，激光雷达接收光信号的单次散射率不断降低，导致激光雷达直接测量的退偏振比的误差随之增大。以100 mrad接收视场角为例，中浓度散射层情况下，在散射层上（0~10 m）、散射层中（10~30 m）和散射层下（30~40 m）的退偏振比相对误差分别为16%、125%、281%；在散射层中，低、中、高三种浓度散射层的退偏振比相对误差分别为54%、125%、731%。视场角从10 mrad增大到1000 mrad时，退偏振比相对误差逐渐增大，在中浓度散射层情况下，其在散射层上、散射层中和散射层下的变化范围分别为6%~28%、17%~452%和10%~734%。文中结果表明，偏振海洋激光雷达探测水体退偏振比时，由于多次散射过程的影响，传统的退偏振比算法会引入较大误差，有必要在反演算法中对其进行校正，以提高激光雷达的探测精度。

We report holographic fabrication of nanoporous distributed Bragg reflector (DBR) films with periodic nanoscale porosity via a single-prism conuration. The nanoporous DBR films result from the phase separation in a material recipe, which consists of a polymerizable acrylate monomer and nonreactive volatile solvent. By changing the interfering angle of two laser beams, we achieve the nanoporous DBR films with highly reflective red, green, and blue colors. The reflection band of the nanoporous DBR films can be tuned by further filling different liquids into the pores inside the films, resulting in the color change accordingly. Experimental results show that such kinds of nanoporous DBR films could be potentially useful for many applications, such as color filters and refractive index sensors.