摘要
本论文介绍了自行研制的一套多幅M-Z激光干涉仪。该干涉仪在小型喷气式Z箍缩装置上进行了实验，在一次等离子体内爆过程中拍摄到时间间隔为13纳秒的三幅干涉图。
多幅M-Z激光干涉仪由激光器、空间分光延时系统，M-Z干涉仪和CCD成像系统构成。所用激光器为Nd:YAG脉冲激光器，采用了调Q和二倍频技术，波长为0.532、脉冲宽度为7ns、相干长度为2cm，能量为35mJ。空间分光延时系统由三对全反镜和部分反射镜构成，根据实验平台大小和实际需要调整镜片之间的距离，使相邻光束之间的光程差为390cm。激光器发出的光束经过分光系统被分成时间间隔13ns的三束光，它们于不同的时刻先后到达M-Z干涉仪，每一束激光脉冲可以记录下等离子的一个状态，从而可以得到三幅不同时刻的干涉图。成像系统由凸透镜（焦距约为40cm）、光楔（楔角为）、成像屏和CCD相机（SONY F707）构成。由干涉仪射出的三束光经凸透镜会聚于空间位置不同的点，把光楔放置在这些点上可使三束光在空间上彼此分开，利用CCD相机可记录下三幅干涉图。
该套干涉仪在小型喷气式Z箍缩装置上进行了实验, Z装置的工作电压23kV、峰值电流210kA、电流上升时间约2。根据干涉图条纹的移动数,可以计算出等离子体的电子密度和运动速度。在箍缩早期平均电子密度为，运动速度为；聚焦附近，等离子体的平均电子密度约为，运动速度，最小箍缩半径0.49mm；崩溃阶段，等离子体的崩溃速度为。此系统属国内首创，实验结果达国际先进水平。
This paper describes a multi-frame Mach-Zehnder (M-Z) interferometer (MFMZI) developed by ourselves. MFMZI was conducted on a small gas-puff Z-Pinch device, and three interferograms with an interpulse delay of 13 ns were obtained in one shot of Z-Pinch.
MFMZI consists of a Nd:YAG laser, a beam-splitter, a M-Z interferometer and a image system. With double-frequency technique and Q switch technique the laser delivers a laser pulse of 532-nm in wavelength, 5-ns in pulse width, 35-mJ in energy and 2-cm in coherent length. The beam-splitter comprises three pairs of fully reflecting planar mirrors and partially reflecting planar mirrors. According to the workspace size and experimental requirement, they were placed with a distance of 195-cm between two mirrors. When passed through the beam-splitter, a pulsed laser beam was split into 3 beams with an interpulse delay of 13 ns. These 3 separated laser pulses reach the M-Z interferometer at different time and each laser pulse gave a snapshot of the implosion state. Thus three different-time interferograms can be obtained in one shot of Z-Pinch. The image system includes a positive lens with 40-cm focal distance, a prism with a angle，a receiving board and a CCD camera with 5.02 million pixels. The laser beams from M-Z interferometer will focus on three different dots after going through the positive lens, and the prisms were placed on these dots. Owing to the deviation of these prisms, three interferograms will be separated each other when they reach the image board. Then these separated interferograms can be recorded by CCD camera
The experiments with the multi-frame interferometer was carried out on a small gas-puff z-pinch device with 23 kV working voltage and 210 kA peak current and about 2 risetime, and good results were obtained. According to the fringe shift of the interferograms, electron density and implosion velocity can be obtained. In the early period of plasma imploding，the averaged electron density is ,
and the averaged implosion velocity is up to; Near the final focus, the smallest radium of plasma shell is about 0.49 mm, and the electron density was estimated to be more than, and the averaged implosion velocity is about ; In the collapsing period, the averaged collapsing velocity is about .
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