Interferometric detection of surface displacement of solid state body - exciting surfaces by illumination laser to produce ultrasonic vibrations and part of reflected radiation impinges on detector

摘要

A part beam of the reflected radiation from the surface (4) of the test material (5) is irradiated in the resonator of the illumination laser (3) acting on it, whilst the remaining reflected radiation is directed on to the detector (7), and its output signal is indicated on a monitor (8). The part beam irradiated in the resonator of the illumination laser amounts to 1-10 percent of the reflected radiation. The reflected radiation remaining for the detector acts on an avalanche diode, the signal of which is supplied to a connected amplifier. The reflected radiation is divided by means of a non-metallised glass plate. USE/ADVANTAGE - Interferometric detection of surface displacement of solid state body. Easily carried out method using conventional HeNe laser at hot and cold solid state samples from a distance up to about 1 metre and load on optics in beam course of laser is reduced.