基于光栅倾斜脉冲前沿的太赫兹脉冲单次测量

Single shot measurement of terahertz pulse based on pulse front tilting by grating diffraction

太赫兹脉冲单次测量技术对于不可逆或者单次超快过程的太赫兹光谱研究具有重要意义。为了实现无畸变的高频率分辨率的太赫兹脉冲单次探测,利用光栅产生了一束具有倾斜前沿的飞秒探测脉冲,并利用该探测脉冲实现了对太赫兹脉冲时域电场波形的单次测量,测量时间范围达到20 ps,频谱覆盖0.1 THz^2.5 THz范围。且测量的结果与使用传统电光采样方法测量的结果相符合。对于基于光栅产生倾斜脉冲前沿的太赫兹脉冲单次测量方法进行了建模分析,获得了光栅和光学元件参数的选取,以及光路设计等指导性结论。

The single shot measurement of terahertz pulse is of great importance to the study of terahertz spectrum on ultra fast irreversible or single shot processes. A femtosecond pulse with tilted intensity front generated by using commercial grating are adopted as the probe beam for the measurement, in order to implement single shot measurement of terahertz pulses with low distortion and high frequency resolution. The time window is up to 20 ps and spectrum range covers from 0.1 THz to 2.5 THz. The result agrees well with that of the traditional electrical-optic sampling method. Analytical model for the single shot measurement of terahertz pulse using tilted pulse front technique is established, and some conclusions concerning the parameters preference of grating and optical system components, as well as optical design, are obtained.