大口径反射镜高反膜是大口径空间相机光学系统中的重要光学元件。为了观测到更多的目标、获取更多的地球以及空间观测信息, 对大口径空间相机的反向射膜提出了更高要求, 即要求有更宽的工作谱段和更高的反射率, 还要提升基底光学性能, 降低空间环境对高反膜性能的影响以及降低薄膜应力等等。对近年国内外天基大口径空间相机反射镜高反膜研究进行了综述, 概述了针对以上要求所取得的成果。尽管高反膜的设计制造仍面临许多困难, 但随着研究的深入与新方法的提出, 这几方面难点已基本找到解决的途径。

本文通过使用多巴胺二硫代氨基甲酸(DDTC)作为还原剂来控制银纳米颗粒以异相成核的生长模式在金立方表面进行生长,合成出“爆米花”状的金银纳米超结构。这种结构的纳米颗粒在可见光区表现出可调谐的等离子体共振特性,并且通过改变硝酸银的浓度能够精细的调节银层的厚度。此外,使用液液界面自组装技术将纳米颗粒组装成单层膜,然后将结晶紫作为探针分子来研究纳米颗粒的表面增强拉曼散射特性(SERS)和银层厚度之间的依赖关系。并系统的研究了三种激发波长对SERS基底的响应。结果表明“爆米花”状的金银核壳超结构具有可调节的局域表面等离子体共振(LSPR)和SERS特性,在太阳能电池、催化、化学传感等领域具有广阔的应用前景。

重复频率激光放大器是实现重复频率激光器的关键器件,其重复频率取决于对抽运及放大过程中产生热量的有效控制。针对千焦耳量级输出重复频率激光器的需求,通过合理的结构设计、冷却液选型及测试等,研制出一台基于氙灯抽运、钕玻璃增益介质、液体冷却、通光直径为Φ130 mm的激光放大器样机。测试结果表明,该放大器样机可实现每分钟一次的重复频率运行,同时具备双程1.3189倍净增益,双程动态波前PV(peak to valley)平均值为0.2718波长(λ)(20 ℃,λ=1053 nm,10发次计)和0.3223λ(30 ℃,λ=1053 nm,10发次计)。

半导体太赫兹量子级联激光器(THz QCL)是一种相干性好线宽窄的太赫兹辐射源, 有潜力获得高的输出功率.采用基于非平衡格林函数(NEGF)方法的计算工具设计、生长、制备了基于砷化镓系材料的THz QCL.在10 K温度下, 峰值功率达到270 mW, 平均功率为2.4 mW, 单位面积的输出功率与已报道的最高值相当.采用NEGF方法对器件的温度变化特性做了详细的分析.

高功率片状放大器在线运行时氙灯辐照导致片腔内产生大量气溶胶，易引起钕玻璃污染，影响其使用寿命。采用洁净氮气吹扫恢复片腔内的洁净环境是片状放大器在线运行时的主要洁净手段。研究了氮气吹扫过程中片腔内涡流对洁净度的影响，结果显示涡流对气溶胶颗粒的禁锢作用会导致腔内气溶胶颗粒的大量残留，且无法通过延长吹扫时间或调整吹扫流速加以解决。针对这一问题，提出了间断多次氮气吹扫对腔内气溶胶进行循环稀释的在线洁净控制方法，该方法使腔内涡流经历不断破坏和重建过程，涡流场内滞留的气溶胶颗粒含量也得到不断稀释，从而大幅提高片腔洁净度。针对Φ130 mm单口径片状放大器进行了对比实验研究。采用间断吹扫法之后，腔内残留气溶胶颗粒为连续吹扫时的1/100，片腔洁净度在15 h的观测时间内始终保持在40级以内。该方法普适有效，为避免片状放大器钕玻璃气溶胶污染,增加其在线使用寿命提供了重要参考。

使用种子生长法制备得到银纳米立方, 扫描电镜的表征结果表明制备得到的银纳米立方尺寸为(61.5±4.4) nm, 相对标准偏差为7.2%。 利用表面替换技术将其表面的CTAC替换为更有利于SERS检测的柠檬酸根。 然后基于具有超润滑特性的SLIPS衬底, 构建出以银立方作为组装单元的具有三维热点的SERS基底。 利用该三维SERS基底分别检测了水中的三环唑和乙醇中的福美双, 检测限分别可达到52.8和41.6 nmol·L-1。 实验结果表明银立方三维热点SERS基底具有较高的灵敏度, 能够应用于多种溶剂中农药的快速检测, 对于实际场景下农药残留的快速检测具有重要的意义。

高功率激光装置中的片状放大器普遍采用高功率脉冲氙灯作为抽运源, 氙灯的辐射光谱与片状放大器的增益性能密切相关。基于暗室中搭建的时间分辨率为2 μs的氙灯光谱测试系统, 测试氙灯在不同放电时刻的辐射光谱。结果表明: 相同电流密度对应的上升沿、下降沿时刻的氙灯辐射光谱存在显著差别, 上升沿光谱的分立谱明显; 当电流密度为0.866 kA·cm-2时, 如果不施加预电离, 上升沿的辐射光谱能量比下降沿低48%, 施加预电离后这种差距缩小至24%; 预电离可以有效提高上升沿时刻的光谱强度, 是提高氙灯辐射效率的有效途径之一; 对氙灯辐射光谱的原模型进行修正, 可使其与测试光谱数据更吻合。

An all-fiber Faraday rotator isolation rate measurement system is designed and realized. The system has tremendous advantage for large aperture Faraday isolator on-line measurement due to its flexible alignment and more compaction. Employing the method of relative transmission measurement and transmissions contrasting between static and operating states, single-shot isolation-rate measurement is achieved. The available measurement range larger than 33 dB is demonstrated experimentally. And the potential to get measurement range larger than 50 dB by adjusting the coupling rate of the fiber couplers is affirmed. Measurement accuracy of 2.2%of PV value is achieved even while keeping the input pulse energy and polarization in random vibration, which illustrates that the influence of the input pulse energy and polarization vibration on the measurement accuracy is eliminated.

An all-fiber Faraday rotator isolation rate measurement system is designed and realized. The system has tremendous advantage for large aperture Faraday isolator on-line measurement due to its flexible alignment and more compaction. Employing the method of relative transmission measurement and transmissions contrasting between static and operating states, single-shot isolation-rate measurement is achieved. The available measurement range larger than 33 dB is demonstrated experimentally. And the potential to get measurement range larger than 50 dB by adjusting the coupling rate of the fiber couplers is affirmed. Measurement accuracy of 2.2%of PV value is achieved even while keeping the input pulse energy and polarization in random vibration, which illustrates that the influence of the input pulse energy and polarization vibration on the measurement accuracy is eliminated.

To overcome the problem of cleanliness in the laser′s internal cavity, a glass cavity design for a Nd: glass slab amplifier was proposed, which uses UV-stop quartz glass for its main structure.The design of the main structure of the glass cavity and the sealing are optimized, and metal-coated surfaces are used to prevent light from escaping.The cleanliness of the stainless steel cavity of the slab amplifier of the SG-II-UP laser and the glass cavity of a 100 slab amplifier were compared; the cleanliness of the glass cavity was found to be 70% better than that of the stainless cavity. Further, advanced system analysis program was used to simulate the designed amplifier, with the pumping ratio of the Nd: glass in the glass cavity being increased by 8.84%.Thus, the glass cavity decreases the production of aerosols and enhances the pumping ratio of the Nd∶glass.