title: Bragg cell laser intensity modulation: effect on laser Doppler velocimetry measurements.
abstract: In most laser Doppler velocimetry (LDV) systems, the frequency of one of the two laser beams that intersect to create the probe volume is shifted with an acousto-optic element. It is shown here that Bragg shifting can impose a problematic fluctuation in intensity on the frequency-shifted beam, producing spurious velocity measurements. This fluctuation occurs at twice the Bragg cell frequency, and its relative amplitude to the time average intensity is a function of the ratio of the laser beam diameter to the Bragg cell acoustic wavelength. A physical model and a configuration procedure to minimize adverse effects of the intensity modulations are presented.
authors: Department of Mechanical Engineering, University of Michigan, Ann Arbor, 1231 Beal Avenue, 2010 Auto Lab, Ann Arbor, Michigan 48109, USA. almych@umich.edu
authors: Alexander G
authors: AG
authors: Mychkovsky
authors: Natasha A
authors: NA
authors: Chang
authors: Steven L
authors: SL
authors: Ceccio