大气湍流对部分相干电磁平顶光束传输的影响

基于相干性和偏振性统一理论,采用Rytov相位结构函数平方近似推导出了部分相干电磁平顶光束在湍流大气中传输的偏振度、相干度和光谱强度公式,并研究了湍流对其传输特性的影响.研究表明,偏振度和相干度与源光谱的带宽无关.大气湍流使得不同阶数的部分相干电磁平顶光束的偏振度经长程传输后均趋于其初始值.大气湍流使得部分相干电磁平顶光束与电磁高斯-谢尔模型光束相干度的差别减小,并导致相干度的振荡和相位奇异现象消失.大气湍流使得相干性较好的部分相干电磁平顶光束的光谱跃变现象消失.

Influence of Atmospheric Turbulence on the Propagation of Partially Coherent Electromagnetic Flat-topped Beams

Based on the extended Huygens-Fresnel principle,the analytical expressions for the degree of polarization,the degree of coherence and the spectrum of partially coherent electromagnetic flat-topped beams in turbulence are derived by using the quadratic approximation of Rytov's phase structure function.The influence of atmospheric turbulence on the propagation property is studied.The propagation property of electromagnetic Gaussian Schell-model (EGSM) beams through atmospheric turbulence is just a special case.It is shown that the degree of polarization and coherence of partially coherent electromagnetic flat-topped beams is independent of the bandwidth.After sufficient long propagation,the degree of polarization of partially coherent electromagnetic flat-topped beams with different beam orders tend to the same value at the source plane due to turbulence.The turbulence makes the difference of the degree of coherence between partially coherent electromagnetic flat-topped beams and EGSM beams decrease.The oscillatory behavior and phase singularities of the degree of coherence of partially coherent electromagnetic flat-topped beams may disappear in the turbulence.The spectral transition of partially coherent electromagnetic flat-topped beams with better coherence may disappear because of turbulence.