Laser Doppler Velocimetry for Two-Dimensional Directional Discrimination by Monitoring Scattered Beams in Different Directions

Abstract

2-D laser Doppler velocimetry without polarization discrimination, wavelength discrimination or frequency-shift discrimination is proposed. In the proposed velocimetry, scattered beams in different directions are monitored with two detection blocks in order to discriminate the direction of velocity. The principle of the proposed velocimetry is described and the discrimination of velocity direction is theoretically analyzed by simulation. The simulation result indicates that the direction of velocity can be discriminated by using the proposed velocimetry as well as the magnitude of velocity.

Doppler shift velocimetry using two point probe nested-microring resonators

“…Many works have been involved and used such devices, the use of nonmechanical scanning laser Doppler velocimeter (LDV) has been proposed, 1 where several works have been proposed by the authors, for instance, the use of optical fiber Mach-Zehnder interferometers for wavelength-insensitive and small wavelength sensitivity, 2 two-dimensional directional discrimination by monitoring scattered beams in different directions, 3 two-dimensional LDV using polarized beams and 90 • phase shift for discrimination of velocity direction, 4 nonmechanical scanning laser Doppler velocimetry with sensitivity to direction of transverse velocity component using optical serrodyne frequency shifting 5 and two-point velocity measurement using diffraction grating elements for integrated multi-point differential. 6,7 The Doppler effect-based fiberoptic (FOD) sensor and its application in ultrasonic detection on the surface of aluminum-alloy plate to generate ultrasonic wave has also been, 8 where the sensitivity was direction-independent and directly proportional to the effective sensing length of the fiber optic sensor.…”