MOPA结构脉冲单频激光器时间相干性的初步实验

The Primary Experiment of Temporal Coherence of Pulse Single-frequency Laser Based on MOPA Structure

为了研制激光干涉成像所需的基于主振荡功率放大（Master Oscillator Power Amplifier,MOPA）结构的高能高相干脉冲单频激光器,需要研究经过功率放大后的脉冲时间相干性随激光功率（或能量）增加的变化趋势。本文采用声光调Q脉冲单频Nd：YVO_4激光器作为种子源,利用Nd：YAG功率放大模块对种子源激光进行2.1倍的脉冲能量放大。利用迈氏干涉测量法,完成种子源和2.1倍功放后激光在0～6 m光程差下干涉条纹对比度的实验测量,从而初步得到脉冲激光时间相干性（线宽）随激光功率（或能量）增加的变化趋势。同时也完成种子源和功放后激光的单频性、单脉冲能量、脉宽和峰值功率等基本参数的实验测量。

In order to manufacture MOPA structure pulse single-frequency laser used for laser coherence imaging,the changes of temporal coherence of pulse single-frequency laser with the increment of laser power is required to be studied.This paper adopted acousto-optic Q-switch pulse single-frequency Nd：YVO_4 laser as seed,and adopted Nd：YAG power amplifier modules to double the power of seed laser.The Michelson interferometry was used to complete the measurement of the contrast of fringes of seed laser and amplifier under the optical path difference from 0 m to 6 m.Then,the change of temporal coherence of pulse single-frequency laser with the increment of laser power was primarily obtained.The measurements of basic parameters of seed laser and amplifier such as the property of single-frequency,pulse energy,pulse width and peak power etc was completed.