VISAR准零程差调试方法研究

Adjustment method for quasi zero optical path difference of VISAR

介绍了任意反射面速度干涉仪(V ISAR)中马赫-曾德干涉仪必须满足的准零程差条件。根据白光光程差调试精度高但不易相干的特点,提出了先利用激光粗调,再利用白光调试来实现零程差精密调节的方案。详细分析了激光粗调马赫-曾德干涉仪的调试原理、调试精度以及光程差不确定性。针对光程差不确定性,提出了改进的激光粗调方案,将光程差调节精度由毫米量级提高到微米量级,大大减小了白光调试的盲区,使白光精调变得简易可行。干涉仪最终光程差调试精度为1.6μm。

The quasi zero optical path difference （OPD） that Mach-Zehnder interferometer must meet is introduced. The scheme that the rough adjustment to the interferometer is performed with laser first, and then the fine adjustment to it is carried out with white light is provided for realizing the precision adjustment for OPD, according to the characteristics that the white light has high accuracy for adjusting OPD but is not easy to be cohered. The alignment principle, accuracy and indeterminacy of OPD for the coarse adjustment of Mach-Zehnder interferometer with laser is analyzed in detail. An improved laser coarse adjustment scheme is put forward to overcome the indeterminacy of OPD, which raises the order of magnitude of OPD accuracy from millimeter to micron, dwindles the dead zone of the white light fine adjustment greatly, and made the white light fine adjustment simple and feasible. The adjustment accuracy of final OPD for the interferometer is 1.6 μm.