为抑制光参量振荡器（Optical Parametric Oscillator，OPO）振荡过程中信号光和闲频光向泵浦光的逆转换，首次采用在L型OPO腔的支路中插入信号光倍频晶体LiB₃O₅的（简称LBO）的方式，实现了BaGa₄Se₇（BGSe） OPO闲频光的高转换效率输出，当泵浦激光（1.06 μm）能量为115 mJ时，闲频光（3.5 μm）能量为16.18 mJ，光光转换效率为14.06%，斜效率为18.4%，这是目前已知1.06 μm激光泵浦BGSe OPO最高的转换效率。模拟了不同泵浦能量下L型腔中有无LBO晶体时BGSe OPO腔内的三波波形，并给出了闲频光在实验中的输出波形。与传统OPO腔相比，所提出的L型OPO腔（含倍频晶体）在大能量泵浦条件下抑制了逆转换，可获得更高的闲频光转换效率。

随着激光技术的迅速发展，激光**装备日益增多，广泛应用各个领域的光电成像系统被激光致盲或致眩的概率骤增，信息获取能力急剧下降，因此，光电成像系统激光防护技术研究变得越来越重要。简要介绍了基于线性材料和非线性材料的光电成像系统激光致盲防护技术的机理及局限，重点阐述了以二氧化钒为代表的基于相变材料的激光致盲防护技术的机理、制备方法和应用进展，详细分析了基于计算成像的激光致盲防护技术的机理和初步应用探索，结合激光致盲与致眩的关系补充说明了研究光电成像系统激光致眩防护技术的必要性和可行性，最后总结了光电成像系统各种激光防护技术的优缺点以及未来发展方向。

The development of laser systems leads to an increasing threat to photoelectric imaging sensors. A cubic phase plate wavefront coding imaging system is proposed to reduce the risk of damage owing to intense laser radiation. Based on the wavefront coding imaging model, the diffracted spot profile and the light intensity distribution on the observation plane are simulated. An experimental device is set up to measure the laser-induced damage thresholds and investigate the morphology of laser-induced damage patterns of the conventional and the wavefront encoding imaging system. Simulations and experimental results manifest the superior laser suppression performance of the proposed method, which can help diminish the undesirable effects of laser irradiation on an imaging sensor.

在碳中和的国际大背景下, 精确可靠地定量测量大气温室气体浓度对实现碳中和目标具有重要意义, 开发测量结果可直接溯源至国际单位制SI的气体分析仪是精确可靠监测温室气体浓度的重要方法。 可调谐二极管激光吸收光谱(TDLAS)技术是常用的气体浓度测量方法, 根据比尔-朗伯定律, 实现仪器的测量浓度直接溯源至SI的必要条件之一是可直接溯源的气池光程, 气池光程的不确定度直接影响气体浓度的测量不确定度, 对气池光程的可溯源精确测量有利于发展测量结果可直接溯源的气体分析仪。 针对光程标称为81 cm的三次反射型气池光程可溯源测量需求, 使用校准的米尺测量该气池光程得到的直接测量结果为(81.21±0.80) cm, 较大的测量不确定度(0.80 cm)是综合考虑定位误差和三段光路与测量路径可能不重合导致的测量误差估算得到的。 为了减小测量不确定度, 本文搭建了TDLAS气池光程测量系统, 测量系统以1 576 nm分布式反馈激光器为光源, 通过在激光控制器上加载斜坡扫描电压来测量待测气池内标准高纯二氧化碳(CO₂, 99.999%)在6 344.68 cm^-1附近的吸收光谱, 使用测量结果可直接溯源的压力传感器和温度传感器分别测量气池内的压强和气体温度, 采用美国国家标准技术局最新测量得到的30012-00001跃迁带P 4e支线强(相对标准不确定度为0.15%)反演气池光程, 使用二次速度依赖Voigt线型精确拟合不同气压(36~75 Torr)下的光谱吸光度信号获得对应气压的积分吸光度, 全面分析各参量的测量不确定度及其传递过程, 对不同气压下的积分吸光度进行线性回归分析, 计算得到可直接溯源的气池光程为(81.61±0.42) cm, 相对标准不确定度为0.51%, 测量不确定度范围落在直接测量结果范围内, 测量不确定度小于直接测量结果。 本文气池的光路结构是多次反射长光程气池的简化, 该系统同样适用于多次反射长光程气池光程的可溯源测量。

The linewidth of the BaGa4Se7 (BGSe) optical parametric oscillator (OPO) was narrowed for the first time, to the best of our knowledge, by inserting a Fabry–Perot (FP) etalon into an L-shaped cavity. When a 15 mm long BGSe (56.3°, 0°) was pumped by a 1064 nm laser, the peak wavelength was ∼3529nm, and the linewidth was 4.53 nm (3.64cm-1) under type I phase matching. After inserting a 350 µm thick FP etalon, the linewidth was decreased to 1.27–2.05 nm. When the tilt angle of the etalon was 2.34°, the linewidth was 2.05 nm (1.65cm-1), and the peak wavelength was still ∼3529nm. When the tilt angle of the etalon was 3.90°, the peak wavelength was 3534.9 nm, and the linewidth was 1.27 nm (1.02cm-1), which was the narrowest linewidth of a BGSe OPO, to the best of our knowledge. The beam quality was also improved after inserting the FP etalon.

The temperature tuning of BaGa4Se7 (BGSe) was demonstrated for the first time, to the best of our knowledge. When the temperature of BGSe (56.3°,0°) was raised from 30°C to 140°C, the idler light under type I raised from 3637 nm to 3989 nm, the tunable range reached 352 nm, and Δλ2/ΔT reached 3.20 nm/°C. We calculated the phase matching curve of BGSe when ? and T took different values. The relationship between θ and Δλ2/ΔT was obtained by fixing ? at 0°. The maximum Δλ2/ΔT and its corresponding (θ,?) phase matching type were reported under different fixed λ2(3μm,3.2μm,…,5μm).