时域飞秒散斑的特性与测量

阐述了飞秒激光脉冲在随机介质传播过程中产生时域散斑的原理,并对时域飞秒散斑进行了测量. 时域飞秒散斑的产生是飞秒脉冲在随机介质中经历多重散射形成的随机干涉现象在时域的体现. 初步讨论了时域散斑的统计特性并给出了相应的实验结果. 关键词： 时域散斑 飞秒脉冲 随机介质     

Wide band polarizer with suspended germanium resonant grating

An ultra broad band polarizer that operates in the telecommunication wavelength band is proposed.This device,which consists of a single suspended germanium resonant grating layer,is designed using the inverse mathematical method and the rigorous vector diffraction theory.Calculated results indicate that the ultra broad band polarizer exhibits extremely high reflection(R > 99%) for TE polarization light and high transmission(T > 99%) for TM polarization at the wavelength range greater than 300 nm,and it has an extinction ratio of approximately 1 000 at the 1 550-nm central wavelength.The results of the rigorous coupled wave analysis indicate that the extremely wide band property of the TE polarization is caused by the excitation of strong modulation guided modes in the design wavelength range.