受光纤中声学声子10 ns的寿命的影响，传统布里渊光时域分析（BOTDA）传感器往往不能做到1 m以内的空间分辨率。利用差分脉冲对（DPP）技术可以突破该限制，实现更高的空间分辨率。但是传统的DPP技术存在测量时间长、差分信号间同步难度高和信噪比低等问题。本文提出一种基于布里渊增益-损耗效应的编码DPP-BOTDA系统，通过将处于斯托克斯频率和反斯托克斯频率的泵浦脉冲光同步注入光纤，利用散射光的布里渊增益-损耗效应在光路上差分，解决了信号间的同步问题，并且测量时间只需要传统DPP技术的一半。还分析了传感系统中掺铒光纤放大器增益特性对脉冲序列解码结果的影响，对增益不均匀条件下的编码增益进行了理论计算。实验结果表明，该系统可以实现50 cm的空间分辨率，与传统的单脉冲DPP-BOTDA系统相比，信噪比提高了3 dB。

Surface defects (SDs) and subsurface defects (SSDs) are the key factors decreasing the laser damage threshold of optics. Due to the spatially stacked structure, accurately detecting and distinguishing them has become a major challenge. Herein a detection method for SDs and SSDs with multisensor image fusion is proposed. The optics is illuminated by a laser under dark field condition, and the defects are excited to generate scattering and fluorescence lights, which are received by two image sensors in a wide-field microscope. With the modified algorithms of image registration and feature-level fusion, different types of defects are identified and extracted from the scattering and fluorescence images. Experiments show that two imaging modes can be realized simultaneously by multisensor image fusion, and HF etching verifies that SDs and SSDs of polished optics can be accurately distinguished. This method provides a more targeted reference for the evaluation and control of the defects of optics, and exhibits potential in the application of material surface research.

Inorganic perovskite solar cells (IPSCs) have attained attention due to their excellent thermal and phase stability. In this work, we demonstrate a novel approach for fabricating IPSCs, using the strategies of interface passivation and anti-solvent before spin-coating perovskite. Poly(methyl methacrylate) (PMMA) and chlorobenzene (CB) are used as passivator and anti-solvent, respectively. The CB improves the perovskite crystal morphology. Meanwhile, PMMA passivates the defects between poly(3, 4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT: PSS) and perovskite layer, thus increasing the short-circuit current. Excitingly, we find that PMMA benefits the grain boundaries (GBs) of perovskite, which makes it more humidity-resistant, increasing the stability of perovskite film. Especially, PMMA mitigates interfacial charge losses, and the devices based on CsPbI3-xBrx passivated by PMMA exhibit the power conversion efficiency (PCE) much higher than those based on pure CsPbI3-xBrx.

熔石英光学元件在高能量密度的紫外脉冲激光辐照下往往极易出现后表面损伤，这严重影响了紫外高功率脉冲激光装置的可靠性。综合国内外相关研究进展，系统阐述了熔石英元件表面在高能量紫外脉冲激光辐照下的损伤特性，包括典型的初始损伤和损伤增长行为特征，介绍了熔石英元件表面缺陷的类型、分布特性和紫外脉冲激光诱导损伤的内在机制，并概述了常用的熔石英表面加工方法与缺陷控制技术。最后，介绍了熔石英表面缺陷无损检测新技术和抗损伤性能测试技术方面的研究进展。

氧化石墨烯是工业常用的化学试剂。为了测试其光热转换性能, 采用了改进的Hummers方法制取氧化石墨烯(GO)分散液, 进而通过静电纺丝制备PVA-GO复合膜, 运用紫外吸收漫反射光谱(UVRS)分析了PVA-GO复合膜的吸光性能, 通过电子天平连接计算机软件测量PVA-GO蒸发水量。结果表明, 在一定范围内, 随着GO质量浓度的增加, PVA-GO蒸发水量不断增加。当GO质量浓度达到7%时, PVA-GO复合膜能够较好地被静电纺丝成纤维网状结构, 同时又具有良好的光热转换效果。通过扫描电镜(SEM)分析PVA-GO复合膜的表面特征, 发现无添加GO的PVA膜是纤维丝状结构, 表面光滑, 且纤维直径大小一致, 分布均匀。当在PVA中填充7%GO时, 纤维网接而成, 部分GO均匀包裹纤维丝。在真空环境下, 423 K高温处理后, PVA-GO复合膜致密度增加, GO附着纤维丝程度提升。当使用980 nm红外激光辐射时, PVA-GO复合膜的蒸发速率为0.81 kg/(m2·h), 约是聚乙烯醇膜的两倍。同时, 蒸发效率达到51%。这不仅提高了光热转换性能, 增加了光能利用率, 还可以为海水淡化的工业应用提供参考。

为了建立有效无损的亚表面缺陷探测技术, 本文开展了光学元件亚表面缺陷的荧光成像技术研究, 通过系统优化激发波长、成像光谱、成像光路及探测器等影响探测精度和探测灵敏度的参数, 研制出小口径荧光缺陷检测样机。基于该样机对一系列精抛光熔石英和飞切KDP晶体元件的散射缺陷和荧光缺陷进行了表征, 获得了各类样品亚表面缺陷所占的比重差异很大, 从0.012%到1.1%不等。利用统计学方法分析了亚表面缺陷与损伤阈值的关系, 结果显示, 熔石英亚表面缺陷与损伤阈值相关曲线的R2值为0.907, KDP晶体亚表面缺陷与损伤阈值相关曲线的R2值为0.947, 均属于强相关。该研究结果可评价光学元件的加工质量, 用于指导紫外光学元件加工工艺, 并且由于该探测技术具有无损、快速的特点, 因此可应用于大口径紫外光学元件全口径亚表面缺陷探测, 具有极其重要的工程意义。

熔融石英光学元件的亚表面缺陷直接影响着其成像质量及激光损伤阈值等指标。相比缺陷的二维截面大小以及深度信息,亚表面缺陷三维轮廓及缺陷体积的定量检测结果可以用来更准确地评估熔融石英光学元件的加工质量。结合共聚焦显微镜的成像原理,使用共聚焦显微镜进行了熔融石英样品层析扫描实验。通过对亚表面缺陷图像特点的分析,提出了适用熔融石英元件亚表面缺陷的三维重建算法。提出的算法在亚表面缺陷重建效率与精度上均优于其他三维重建方法。根据重建后缺陷的统计结果,定量获得了熔融石英样品亚表面缺陷的完整三维信息。