Three interfering beams in laser Doppler velocimetry for particle position and microflow velocity profile measurements.
It is proposed to use three interfering and coplanar laser beams to form the probe volume of laser Doppler systems. This allows us to obtain, for each particle crossing this probe volume, a Doppler signal whose frequency amplitude spectrum exhibits two characteristic peaks. Electromagnetic calculations and experimental validations clearly demonstrate that we can estimate simultaneously, from the analysis of these two frequency peaks, the particle position along the optical axis and one velocity component. This technique is expected to have great potentialities for velocity profile measurements in microfluidic or boundary layer flows, as well as for the sizing of spherical particles.
Onofri
Fabrice
F
Institute Universitaire des Systèmes Thermiques Industriels, Unité Mixte de Recherche 6595, Centre National de la Recherche Scientifique, Université de Provence, France. fabrice.onofri@polytech.univ-mrs.fr