title: Spatially encoded multibeam laser Doppler vibrometry using a single photodetector.
abstract: A laser Doppler vibrometer with single photodetector is introduced to measure the vibration on multiple points of target simultaneously. A 2 x 5 beam array with various frequency shifts is generated by three acousto-optic devices, illuminating different points on a vibrating object. The reflected beams interfere with a reference beam on a high-speed photodetector, and the signal is amplified and digitized with a rate of 500 megasamples/s. To extract vibration information of different points, the carrier frequencies of each beam are elaborately designed so that they can be separated from cross-talk regions in the spectrum. The experimental results are compared with that from a commercial single-point vibrometer, and the comparison shows that it is possible to do a precise measurement on multiple points simultaneously using a single photodetector.
authors.affiliation: Temasek Laboratories and School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Drive, Singapore 637553.
authors.forename: Y
authors.initials: Y
authors.lastname: Fu
authors.forename: M
authors.initials: M
authors.lastname: Guo
authors.forename: P B
authors.initials: PB
authors.lastname: Phua