| 摘要 |
FIELD: measurement technology, various fields of science and technology where sound velocity in clear liquids and solid bodies should be determined. SUBSTANCE: according to invention traveling acoustic wave is excited in examined medium, light beam which diameter and length of specified wave are values of same order is directed into region of propagation of wave in examined medium, variable components of intensity of light beam in two points spaced apart through known value in direction of wave propagation are recorded across outlet from medium, phase difference of mentioned variable components is determined and used to make judgment on wave velocity. Variable components of intensity of light beam are recorded in Fresnel diffraction zone and spacing of recording points is selected by smaller diameter of light beam in same recording plane. In particular case variable components of intensity of light beam are recorded at distance from examined medium corresponding to maximum of amplitude of specified variable components and light beam is transmitted in direction perpendicular to direction of wave propagation. In this case intensity of acoustic wave and length of beam path are so selected that condition of Raman-Nath diffraction is secured. EFFECT: simplified realization of procedure and reduced measurement volume. 2 cl, 2 dwg |
