光束变换环形孔径有源激光谐振腔模式的数值模拟

建立了燃烧驱动环柱型高能化学激光器环形增益介质的五种分布模型，使用差分和积分相结合的方法计算了束变换环孔腔在不同增益分布和折射率分布时的模式特征，研究了增益分布和折射率分布对束变换环孔腔输出性能的影响，结果表明束变换环孔腔在不同的增益介质及折射率分布情况下，仍然可以保持良好的输出光束质量，很高的提取效率，在化学激光器增益流存在激波扰动的情况下，输出光场的施特雷尔比仍达到0．8991，同时腔镜上光强分布较为均匀，可以避免镜面因热应力分布不均匀而造成镜面变形和破坏。该腔不但适用于高能化学激光器，也可以用于高能固体激光器，起到克服固体增益介质热畸变与热应力的作用，可获得优良的输出光束质量。

Numerical Simulation of Beam-Converting Annular Resonator with Active Medium

Beam-converting annular resonator (BCAR) possesses outstanding characteristics of high extraction efficiency and near-diffractive beam quality. It is applied specially to annular HF/DF gain medium. A finit difference method is used to calculate the modes of BCAR with various active medium. It showed that BCAR is insensitive to aberrations introduced by active medium, the optical quality is excellent, and extraction efficiency of BCAR is high under all the conditions. When a shock wave exists in the active medium, Strehl ratio of BCAR can still reach 0.899, the intensity distribution on cavity mirrors is reasonable, thus the damage possibility resulting from thermal load on the mirrors is lower than the usual unstable resonators. All above advantages make BCAR a very useful resonator applied not only to high energy chemical lasers but also to other high energy lasers with annular gain medium.