在固体透明材料中利用级联四波混频方法获得宽带多色飞秒激光脉冲的研究

摘要

飞秒激光光谱学实验研究的深入与拓展对飞秒激光脉冲的要求也越来越高.比如多色抽运探测实验需要同时用到多个不同频率的超短飞秒激光脉冲.本文设计了一个更加简单紧凑的实验装置,对两束不同中心频率的入射光引入相反啁啾,在厚度为0.5 mm的CaF2晶体中利用级联四波混频获得了光谱半高全宽近100 nm,支持傅里叶转换极限脉宽小于10 fs的多色飞秒激光脉冲.这一结果将为拓展飞秒激光光谱学研究和应用发挥重要作用.%Femtosecond laser pulses with new properties have been required for the great progress of femtosecond laser spec-troscopy experiments. For example, simultaneous multiple ultrashort femtosecond laser pulses with different frequencies are needed in multicolor pump-probe experiments. Here, we have designed a much more simple and compact system for multicolor femtosecond pulse generation by using cascaded four-wave mixing in a 0.5 mm thick CaF2 plate. Multicolor femtosecond pulses with a sub-10 fs Fourier transform limit pulse width have been obtained by using two oppositely chirped incident pulses. These ultrashort multicolor femtosecond pulses will be used as a new laser source in femtosecond laser spectroscopy.