为了实现可见光波段多路不同波长激光的周期性闭环校正，设计了一种具有光束指向和位置偏差独立监测与调节的激光合束系统。首先，根据系统的应用需求，提出了合束系统的设计指标与整体合束方案。然后，在合束方案的基础上，建立了合束系统的光束控制模型，并通过数值仿真得到了合束系统光束控制的解算方法。闭环合束系统通过光束指向和位置监测装置分别实现合束激光指向偏差与位置偏差的独立监测，并根据监测结果进行光束调节装置控制量的解算；进而通过两维摆镜和一维平移台分别实现光束指向和位置偏差的独立高效调节。最后，采用两路不同波长的激光束，配合光束监测与调节装置，搭建了闭环合束模拟实验平台，对周期性闭环合束系统的合束效果进行了验证。实验结果表明：在长时间的工作过程中，两路激光均实现了与基准光路的精密合束，合束指向精度优于±7 μrad，位置精度优于±0.84 mm。本研究所组建的激光合束系统不仅具有合束精度高、校正速度快、光路扩展性强的优势，而且可实现激光束的周期性闭环校正，能够有效保证合束激光的长期工作稳定性。

Shaping the light beam is always essential for laser technology and its applications. Among the shaping technologies, shaping the laser in its Fourier domain is a widely used and effective method, such as a pulse shaper, or a 4f system with a phase mask or an iris in between. Orbital angular momentum (OAM) modes spectrum, the Fourier transform of the light field in azimuth, provides a perspective for shaping the light. Here, we propose and experimentally demonstrate a shaping strategy for the azimuthal field by modulating the complex amplitude of the OAM mode spectrum. The scheme utilizes multi-plane light conversion technology and consists only of a spatial light modulator and a mirror. Multiple functions, including beam rotating, beam splitting/combining in azimuth, and OAM mode filtering, are demonstrated. Our work provides a compact and programmable solution for modulating the OAM mode spectrum and shaping beams in azimuth.

为解决激光应用中的光束指向抖动问题，提出一种基于高斯过程回归（Gaussian process regression）的激光光束指向稳定性优化方案。介绍了激光光束指向稳定系统装置构成及原理，论述了高斯过程回归方法的原理及其作为激光光束快速稳定控制算法的优势。经过该方法优化后，指向抖动达到水平方向2.3 μrad, 竖直方向3.3 μrad，将激光系统指向稳定性提高了1个数量级以上。指向性抖动为已有线性反馈系统的20 %，尤其对于高频噪声优化有显著效果。该研究对于激光光束指向性敏感的精密实验和精密加工具有重要意义。

设计并制作了一款直径为1.1 mm、频率为31.11 kHz的MEMS压电微镜，用于需要高速扫描且小尺寸的应用场景。该器件所需模态为扭转模态，与其他模态分离情况好，不会出现耦合。实验结果显示，电压为32 V时光学扫描角40.66°，品质因子1 155。改变PZT极性，实验得到了薄膜材料的铁电性质影响。另外，完成了MEMS微镜在0 ℃~100 ℃不同温度下角度的变化实验，偏离不超过±1°。仿真模拟、实验结果和理论计算结果三者拟合情况好，表明该设计的微镜具有较高的可控性和稳定性，为实现高精度扫描提供了有力支持。该MEMS压电微镜在AR/VR等领域中具有潜在的应用前景。

介绍了真空通道应力补偿结构的基本工作原理；研究了大温差环境下，激光束长距离真空传输通道的真空负压应力和热胀冷缩应力的自适应补偿技术和光学舱结构变形抑制技术；在整个光学系统上，开展了现场安装调试和真空负压应力考核，并进行环境温差变化情况下的光路传输稳定性试验验证。试验结果表明：解决了超长激光束真空传输通道在真空负压和大温差环境下的真空负压应力和热胀冷缩应力的自适应补偿问题和光学舱结构变形抑制问题；实现了传输通道真空负压应力自动平衡；消除了真空负压应力造成的光束漂移；实现了大温差环境下的真空负压通道结构热胀冷缩应力的自由释放；达到了光路长时间保持稳定的实际效果。

The laser-induced damage threshold (LIDT) of plate laser beam splitter (PLBS) coatings is closely related to the subsurface absorption defects of the substrate. Herein, a two-step deposition temperature method is proposed to understand the effect of substrate subsurface impurity defects on the LIDT of PLBS coatings. Firstly, BK7 substrates are heat-treated at three different temperatures. The surface morphology and subsurface impurity defect distribution of the substrate before and after the heat treatment are compared. Then, a PLBS coating consisting of alternating HfO₂–Al₂O₃ mixture and SiO₂ layers is designed to achieve a beam-splitting ratio (transmittance to reflectance, s-polarized light) of approximately 50:50 at 1053 nm and an angle of incidence of 45°, and it is prepared under four different deposition processes. The experimental and simulation results show that the subsurface impurity defects of the substrate migrate to the surface and accumulate on the surface during the heat treatment, and become absorption defect sources or nodule defect seeds in the coating, reducing the LIDT of the coating. The higher the heat treatment temperature, the more evident the migration and accumulation of impurity defects. A lower deposition temperature (at which the coating can be fully oxidized) helps to improve the LIDT of the PLBS coating. When the deposition temperature is 140°C, the LIDT (s-polarized light, wavelength: 1064 nm, pulse width: 9 ns, incident angle: 45°) of the PLBS coating is 26.2 J/cm², which is approximately 6.7 times that of the PLBS coating deposited at 200°C. We believe that the investigation into the laser damage mechanism of PLBS coatings will help to improve the LIDT of coatings with partial or high transmittance at laser wavelengths.