基于FFT算法的激光有源非稳腔光场分布数值计算方法  

Numerical Calculation Method of Light Field Distribution for Active Unstable Cavity Resonator Based on FFT Algorithm

作　　者：罗萍萍[1,2] 桑思晗 史文宗 杨超[1,2] 颜凡江 李梦龙 蒙裴贝[1,2] LUO Pingping;SANG Sihan;SHI Wenzong;YANG Chao;YANFanjiang;LI Menglong;MENG Peibei(Beijing Institute of Space Mechanics & Electricity, Beijing 100094, China;Key Laboratory for Space Laser Information Perception Technology of CAST, Beijing 100094, China)

机构地区：[1]北京空间机电研究所,北京100094 [2]中国空间技术研究院空间激光信息感知技术核心专业实验室,北京100094

出　　处：《航天返回与遥感》2019年第4期86-94,共9页Spacecraft Recovery & Remote Sensing

摘　　要：在激光器应用中,激光发散角是重要的技术指标,可由光场分布得出。非稳腔由于易于实现高光束质量输出的优势,是激光器的常用腔型。为了快速获得有源非稳腔激光器的光场分布,提高激光器设计仿真效率,在参考了现有激光器谐振腔数值算法的基础上,建立了一种基于快速傅里叶变换算法的有源谐振腔光场分布计算模型;基于该模型,开展了有源非稳腔的谐振腔特性研究,重点分析了小信号增益分布、输出镜反射率分布及谐振腔的腔镜失谐等因素对激光器光场分布的影响,并量化分析了上述参数对激光器发散角的影响;同时,通过搭建激光器样机,获得了激光输出光斑分布、失谐发散角参数等试验结果,并与光场分布计算模型的计算结果进行了对比分析,认为两者的光斑分布及发散角随腔镜失谐角度变化的趋势大致相同,验证了光场分布计算模型的正确性。因而,在有源谐振腔设计中,应用文章中建立的计算模型,可以对激光器的泵浦设计、腔镜参数选择等提供直观、量化的参考。In laser applications, laser divergence angle is an important technical index, which can be obtained from light field distribution. Unstable cavity is the common cavity type of laser owing to its advantage of easy realization in high beam quality output. In order to quickly obtain the light field distribution of the active unstable resonator laser and improve the simulation efficiency of laser design, a calculation model of the light field distribution of the active resonator based on fast Fourier transform algorithm is established on the basis of the existed numerical algorithm of laser resonator. Based on the obtained model, the resonant cavity characteristics of the active unstable cavity are studied. The influences of small signal gain distribution, output mirror reflectivity distribution and cavity mirror detuning of the resonant cavity on the laser light field distribution are emphatically analyzed, and then the influences of the above parameters on the laser divergence angle are quantitatively computed. At the same time, the experimental results of laser output spot distribution and detuned divergence angle parameters are obtained by setting up a laser prototype, and compared with the calculation results of the light field distribution calculation model. It is believed that the variation trend of the spot distribution and divergence angle in the test and simulation are approximately same with the change of the detuned angle of the cavity mirror, which verifies the correctness of the light field distribution calculation model. Therefore, in the design of active resonant cavity, the proposed calculation model can provide intuitive and quantitative reference for the pump design of laser and the parameters selection of cavity mirror.

关 键 词：有源谐振腔 光场分布 数值计算 激光器 航天遥感 

分 类 号：TN248.1[电子电信—物理电子学]