Laser Interferometer for High Sensitivity Measurements on Transient Phase Objects

Abstract

A He-Ne laser beam is sent through a common path differential interferometer and the interference signal is detected by a p-i-n photodiode. Weak phase objects can be examined because optical path changes can be resolved to 0.1 Å with a time resolution of about 20 ns. Examples for different gas-dynamic investigations show good results and demonstrate the wide field of application for this type of laser interferometer.