湍流对环状光束扩展的影响

采用积分变换技巧，推导出了环状光束通过湍流大气传输二阶矩束宽的解析表达式，并研究了湍流对环状光束扩展的影响.另一方面，通过分析二阶矩束宽给出了环状光束不受湍流影响的传输范围，指出环状光束将不受到湍流大气影响的条件.研究表明，光束遮拦比ε、阶数M（N）、波长λ越大，束宽w₀越小，则环状光束受湍流大气的影响就越小.并对所得到的主要结果给出了合理的物理解释. 关键词： 环状光束 大气湍流 二阶矩束宽

Influence of turbulence on the spreading of annular beams

The closed-form expression for the mean squared beam width of annular beams propagating through atmospheric turbulence is derived by using the integral transform technique. The influence of turbulence on the spreading of annular beams is studied. On the other hand，the range of turbulence-independent propagation is obtained by examining the mean squared beam width，which indicates under what circumstances annular beams will be less affected by turbulence. It is shown that annular beams with larger obscure ratio ε，larger beam order M（N），larger wave length λ，and smaller outer radius w₀ are less sensitive to the turbulence than those with smaller ε，M（N），λ，and larger w₀. The main results obtained in this paper are explained physically.