高斯-谢尔光束通过湍流大气任意粗糙目标的散射统计特性

Statistical properties of a Gaussian-Schell model beam from a semi-rough target in the atmospheric turbulence

基于广义惠更斯-菲涅耳原理和任意粗糙目标模型,考虑大气湍流对激光从发射机到目标和从目标到接收机的影响,研究部分相干高斯-谢尔光束经任意粗糙目标散射后的统计特性.我们假设相位结构函数占优,推导了接收场处互相关函数的表达式,平均强度以及波前相干长度大小,并对此进行数值模拟.结果表明,接收面的平均强度与粗糙面的横向相关长度与表面高度均方根有关;接收场的波前相干长度与湍流强度、表面粗糙度、传播距离和光源相干度有关.

Based on extended Huygens-Fresnel principle and Goodman model for target surface, the treatment includes the effect of the atmospheric turbulence both on the Gaussian- Schell model beam propagates to the target and the scattered field propagates back to the receiver. An expression is developed for the mutual coherent function （MCF） of a reflected Gaussian-Schell model beam from a semi-rough target in atmospheric turbulence. It is assumed that the phase perturbation of the wave is dominant effect due to the atmosphere. Then according to the MCF we derive an expression about the mean intensity and the wavefront coherence length at the receiver. The analysis indicates that the mean intensity is closely related to the ratio of root mean square （RMS） height to the lateral correlation length; in addition, the wavefront coherence length in the receiver is associated with turbulence strength, propagation distance, source coherence parameter and roughness of target.