涡旋光束携带的轨道角动量在自由空间光通信中具有非常重要的意义。本文采用软边小孔改进了基于小孔衍射的涡旋光束轨道角动量检测技术。相比硬边小孔，软边小孔的菲涅尔衍射具有一定的收敛性，能够提高远场衍射分布中主亮斑对次亮斑的相对强度，从而提高主亮斑的可识别度并且拓展基于小孔衍射的轨道角动量范围。通过计算远场衍射中主、次亮斑的强度对比值和主亮斑区域波峰、波谷强度平均对比值来选取合适的超高斯阶数以达到最佳的检测效果。结合理论模拟和实验可知，采用软边矩孔可将涡旋光拓扑荷的可检测范围从硬边矩孔的20阶进一步提高到30阶，采用软边三角孔可将检测范围从±10阶提高到±20阶。

激光无线能量传输在无人机、卫星空间站和探月机器人供电等方面具有潜在应用前景，其系统效率成为了其应用的关键瓶颈。为了提高激光无线能量传输系统发射端激光器的电光转换效率、接收端光斑均匀性和有效窗口收光比，提出了用于激光无线能量传输发射端的高效率半导体激光器设计方案。基于合束效率较高的空间合束设计了一套高功率高效率半导体激光系统，接收端光斑不均匀度可优化至0.207，有效窗口内收光比大于94%。搭建了千瓦级激光无线能量传输实验装置，发射端半导体激光系统直接输出矩形光斑，与矩形光电池匹配，提高了电池阵布片率。利用多光束指向性可调节特点，优化了接收端光斑均匀度，有利于提高接收端电池的转换效率及简化电源管理。该设计与研究为激光无线能量传输的实际应用提供了借鉴意义。

The output performances of a bidirectional ring amplifier with twin pulses are demonstrated. Compared to the extraction efficiency of 32% for single-pulse injection, the extraction efficiency of stored energy for twin-pulse injection with bidirectional propagation is increased to 60%. The maximum output energies of the twin pulses are 347 mJ and 351 mJ, and the output energy of a single pulse is only 373 mJ under the same amplifier operating conditions. The experimental results show that the bidirectional ring amplifier with twin pulses can achieve a higher extraction efficiency of stored energy at a lower operating fluence, and has potential applications in high-power and high-energy laser facilities.

A band-stop angular filter (BSF) based on hump volume Bragg gratings (HVBGs) is proposed. Band-stop filtering in a two-stage amplifier laser system is discussed and simulated. Simulation results show that small-scale self-focusing effects in the laser system can be effectively suppressed with the BSF due to the control of fast nonlinear growth in a specific range of spatial frequencies in the laser beam. Near-field modulation of the output beam from the laser system was decreased from 2.69 to 1.37 by controlling the fast nonlinear growth of spatial frequencies ranging from $0.6~\text{mm}^{-1}$ to $1.2~\text{mm}^{-1}$ with the BSF. In addition, the BSF can be used in a plug-and-play scheme and has potential applications in high-power laser systems.