伪部分相干高斯-谢尔模型光束在湍流大气中传播的闪烁孔径平滑效应

采用光传播的数值模拟方法, 对伪部分相干高斯-谢尔模型光束大气传播过程进行数值模拟, 统计分析不同接收口径内的光强起伏特性,计算闪烁的孔径平滑因子, 讨论了表征伪部分相干光的调制相位屏的相对变化频率对闪烁指数的影响, 并将其与充分发展的部分相干高斯-谢尔模型光束及完全相干光的闪烁指数对比. 结果表明: 降低光源相干性可大幅度降低闪烁指数, 但同时其闪烁指数的孔径平滑效应减弱, 在相同接收孔径下, 伪部分相干光闪烁指数的孔径平滑效果要比完全相干光差; 增大调制相位屏的相对变化频率可在一定程度上降低闪烁指数, 随着其相对频率的增大, 伪部分相干光的闪烁指数与部分相干光的结果趋于一致. 关键词： 伪部分相干高斯-谢尔模型光束 湍流大气 孔径平滑闪烁指数 数值模拟

The aperture averaging effect of scintillation of pseudo-partially Gaussian-Schell model beam propagation in turbulent atmosphere

By using numerical simulation, the propagation of pseudo-partially coherent Gaussian-Schell model beam in atmospheric turbulence is simulated. The properties of intensity fluctuation of different receiving aperture and aperture averaging factors are statistically analyzed. And the influence of relative changing frequency of the modulating phase which models the partial coherence of beam source on scintillation index is also discussed. The simulation results of pseudo-partially coherent beam are compared with those of the well-developed partially coherent beam and fully coherent Gaussian beam. It is found that the reduction of coherence degree may cause scintillation index to decrease. However, the aperture averaging effect is weakened at the same time. At the same receiving aperture diameter, the aperture averaging factor of pseudo-partially coherent beam is greater than that of the fully coherent beam. The increase of relative changing frequency of modulating phase may cause a reduction of scintillation index to some degree. And with the increase of relative changing frequency, the scintillation index of pseudo-partially coherent beam tends to be coincident with that of the partially coherent beam.