用等值宽度法测量fs脉冲宽度

Measurement of femtosecond pulsewidth with interference correlation

本文提出利用等值宽度测量fs光脉冲持续时间的方法.给出了脉冲形状为sech^2 (t/T)、exp(-2t^2/T^2)和exp(-2|t|/T)的干涉相关曲线上包络与相应二阶强度相关曲线半宽度等值的位置,它们分别是3.984、4.875和4.928.定义了两种相关测量的临界延迟速度.理论分析与实验结果符合得很好.所得结果表明,该测量方法可将常规超短脉冲相关测量的时间分辨率提高几倍至几十倍.

A new technique for measurement of femtosecond pulsewidth is proposed with equality-width in this paper. The positions on the up-envelope of interference correlation curve are given at which the envelops width equals FWHM of the second order intensity correlation curve. They are 3.984, 4.875 and 4.928 corresponding to pulse shape of sech2t/T, exp(-2t2/T2) and exp (-2t/T), respectively. The critical delay velocities for two kinds of correlation measurement are defined. Theoretical analysis is in good agreement with experiment. The results show that the measurement method can enhance the resolution of correlation measurement of ultrashort pulse to a few or even tens times.