激光空间相干性对照明均匀性的影响

研究了激光相干性对照明均匀性的影响，为照明激光器的选择提供了理论参考。其中，部分相干高斯光束分解为模式间相互独立的厄米-高斯光束的迭加。采用相位屏的近似处理方法对激光通过大气湍流的传输进行计算模拟。数值模拟的结果表明：当照明光束的空间相干性降低时，其照明均匀度逐步提高。因此对于照明激光器而言，选择空间相干性较差的激光器对其照明均匀度更加有益。

Influence of laser spatial coherence on illumination uniformity

The influence of laser spatial coherence on illumination uniformity is studied in this paper. Partially coherent Gaussian beam is expanded into an independent superposition of Hermite-Gaussian modes. The coherence length of partially coherent Gaussian beam can be derived from its M2 factor. The larger the M2 factor, the shorter the coherence length. Propagation of laser beam through atmospheric turbulence is treated with phase screen approximation. The uniformity of illumination beam is expressed by s 2I . s 2I of partially coherent beams with different M2 factor is computed after propagation through atmospheric turbulence. Th e results of numerical simulation show that illumination uniformity is improved with the decrease of illumination laser spatial coherence.