研制了两幅激光差分干涉诊断系统，可在一次实验中获得两幅间隔3～12 ns的高分辨干涉图像。该系统采用分光延时装置产生两束有一定夹角和时间间隔的探测激光脉冲，采用特殊的偏轴4f传像系统在同一块CCD的不同区域产生两幅干涉图像。应用该系统开展了铝丝阵Z箍缩激光干涉诊断实验，获得了丝膨胀和消融、晕等离子体产生和发展、以及先驱等离子体产生和发展等Z箍缩演化过程的实验图像，并给出了Z箍缩早期阶段的等离子体电子密度分布。

A twoframe laser differential interferometer system has been developed, with which two highdefinition interferograms with an interval of 3 ns12 ns can be obtained in one shot. The system generates two probe pulses with certain intersection angle and time interval via a beam splitting and delaying device. A special offaxis fourfocus imaging system is used to image the object on two different areas on a single CCD ship. The system is applied to aluminum wires Zpinch experiments. Interferograms of Zpinch plasma evolution are obtained, including wires expanding and ablation, generation and evolution of corona plasma and precursory plasma, etc. Electron density distributions of earlystage Zpinch plasma are calculated from the interferograms.