【摘要】 从平面波的角谱表示出发 ,研究了超短光脉冲通过分层介质的远场频谱特性 作为一个例子 ,对飞秒高斯脉冲光束通过位于自由空间中均匀介质薄膜的远场透射谱进行了分析讨论 ,数值计算结果显示远场谱明显不同于入射光场谱分布 ,在不同的观察方向上可呈现谱线变窄、红移、蓝移以及分裂成双重谱线的现象 频移量的大小和谱分布形式与介质参量以及脉冲的谱线宽度、有效空间宽度和观察方向有关更多还原

【Abstract】 Far zone spectral properties of ultrashort pulses transmitted through a stratified medium are studied by using the representation of an angular spectrum of plane waves. As an example, the far zone spectra of a femtosecond light pulse with Gaussian shape transmitted through a dielectric film in free space are analyzed in detail. Results of numerical calculations show that the normalized far zone spectra may change in many different ways, compared with the incident field, exhibiting red shifts, blue shifts, line narrowing and splitting into double lines. The magnitude of the shift and the form of the spectral distribution depend on the parameters of the dielectric film, the spectral linewidth and the effective spatial width of the pulse, and the direction of observation.更多还原