FIELD: physics.
SUBSTANCE: in the method, the emitter used is a helium-neon active element which is optimised to obtain laser radiation at wavelength 3.39 mcm and placed in a semiconfocal cavity with two reflecting surfaces. The radius of curvature of the concave mirror is comparable with double the length of the active element. The analysed surface is used as the second reflecting surface of the cavity. The axis of the cavity is adjusted perpendicular to the analysed surface until generation occurs and maximum value thereof is obtained. The length of the cavity is readjusted during scanning of a spherical mirror within the wavelength and the value of output laser power is measured. The length of the cavity is adjusted on the linear part of the curve of laser power versus the length of the cavity and the variable component of laser power, proportional to surface vibrations, is measured. The variable component of the photodetector is analysed and the amplitude and frequency of vibrations of the analysed surface are determined via Fourier or wavelet transform.
EFFECT: wider frequency range of measured amplitude values of nanovibrations and enabling contactless measurement of absolute dynamic displacements of the probed surface with micron spatial resolution.
2 dwg
