BICHROMATIC LASER DOPPLER VELOCIMETERS
Yu. N. Dubnishchev1,2,3, T. Ya. Dubnishcheva4, V. G. Nechaev2
1Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State Technical University, Novosibirsk, Russia
3Design and Technology Institute of Scientific Instrument Engineering, Novosibirsk, Russia
4Novosibirsk State University of Economics and Management, Novosibirsk, Russia
Keywords: бихроматический лазерный доплеровский измеритель вектора скорости, двухволновой одноканальный акустооптический модулятор, бесселевский лазерный доплеровский анемометр, bichromatic laser Doppler velocimeter, two-wave single-channel acousto-optical modulator, Bessel laser Doppler anemometer
Abstract
The possibility of constructing laser Doppler velocimeters based on the use of a bichromatic source of spatially combined Gaussian or Bessel beams and a two-wave Bragg single-channel acousto-optical modulator with a ratio of ultrasonic wave frequencies equal to the ratio of the wave numbers of diffracting laser beams is discussed. The spatial, chromatic, and frequency structure of the 3D coordinate-measuring basis, formed from Gaussian or Bessel beams by the same sequence of optical elements, and the photoelectric transformation adequate to the structure of light scattered by the medium under study ensure the minimum hardware width of the Doppler signal spectrum and increased noise immunity.
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