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Proceedings Paper

Laser beam refraction in acoustic field
Author(s): O. A. Evtikhieva; I. L. Raskovskaya
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Paper Abstract

The distortions of a laser beam field caused by refraction effects are investigated. We solve the problem in the approximation of geometrical optics using methods of eikonal and amplitude perturbation. The intensity envelope distortions caused by convergence and divergence of geometrical rays inside the laser beam is analyzed. Analytical expressions describing the trajectory of a laser beam propagating in a medium with a weak perturbation of the refractive index caused by an acoustic wave are derived. The effects related to the spatial boundedness of the beam are studied. Based on a unified representation valid for a wide range of ratios of the acoustic wavelength to the beam radius, an interpretation of the refraction effects is presented. The distortions of the beam phase resulting from ray's refraction and corresponding increase of optical path are analyzed. The phase distortions are shown at an interference of two laser beams, for example in laser Doppler anemometer (LDA) applied for sound field diagnostics. An experimental setup has been designed to verify the theoretical investigations and to measure the acoustic field parameters. The values of the beam intensity deviations caused by refraction effects are measured and good agreement with calculation is obtained. The results derived may be used for recommendations giving for performing LDA measurements in the presence of acoustooptic effect (AOE).

Paper Details

Date Published: 10 June 2006
PDF: 8 pages
Proc. SPIE 6262, Optical Methods of Flow Investigation, 626209 (10 June 2006); doi: 10.1117/12.683010
Show Author Affiliations
O. A. Evtikhieva, Moscow Power Engineering Institute Technical Univ. (Russia)
I. L. Raskovskaya, Moscow Power Engineering Institute Technical Univ. (Russia)

Published in SPIE Proceedings Vol. 6262:
Optical Methods of Flow Investigation
Yuri N. Dubnistchev; Bronyus S. Rinkevichyus, Editor(s)

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