Pan Liuzhan, Yuan Xiao, Ding Chaoliang, Lü Baida
Department of Physics, Luoyang Normal College, Luoyang, China.
J Opt Soc Am A Opt Image Sci Vis. 2008 Aug;25(8):2122-8. doi: 10.1364/josaa.25.002122.
Taking the Gaussian Schell-model (GSM) beam as a typical example of partially coherent beams, the analytical expressions of the spectrum of GSM beams propagating in dispersive media are derived, and the spectral properties are studied in detail. It is shown that, in comparison with propagation in free space and in turbulence, whether or not GSM beams satisfy the scaling law, the normalized spectrum of GSM beams in dispersive media changes on propagation in general, because the dispersive medium affects different spectral components differently. As compared with the free-space propagation, for the scaling-law GSM beams the dispersion results in spectrum change, and for the nonscaling-law GSM beams the dispersion gives rise to a further increase in spectral changes. The structure constant of the dispersive property of the media, the transverse coordinate of the observation point, the spatial correlation length of the source, and the propagation distance affect the spectral behavior of GSM beams; this effect is illustrated numerically.
以高斯谢尔模型（GSM）光束作为部分相干光束的典型例子，推导了GSM光束在色散介质中传播时光谱的解析表达式，并详细研究了光谱特性。结果表明，与在自由空间和湍流中的传播相比，无论GSM光束是否满足标度律，色散介质中GSM光束的归一化光谱在传播过程中通常都会发生变化，这是因为色散介质对不同光谱分量的影响不同。与自由空间传播相比，对于满足标度律的GSM光束，色散导致光谱变化，而对于不满足标度律的GSM光束，色散会使光谱变化进一步增大。介质色散特性的结构常数、观测点的横向坐标、光源的空间相关长度以及传播距离都会影响GSM光束的光谱行为；文中通过数值计算对这种影响进行了说明。
