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Optical Engineering

Automatic heterodyning in fiber optic speckle pattern interferometry using laser velocimetry
Author(s): Jesus D. R. Valera; David Harvey; Julian D. C. Jones
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Paper Abstract

We combine the operational advantages ofthe complementary techniques of electronic speckle pattern interferometry (ESPI) and laser Doppler velocimetry (LDV) for out-of-plane vibrational analysis. A cw laser was used in a fiber optic system to generate time-averaged ESPI fringes. By mutual phase-locking of the ESPI and LDV signals, automatic heterodyning of the ESPI signal was achieved (i.e., without operator intervention) together with compensation for unwanted nondeterministic out-of-plane whole-body motion of the object under study. Automatic heterodyning extends the operating range of time-averaged ESPI systems to higher vibrational amplitudes and reveals phase relationships in the object vibration. A practical demonstration of the technique is described.

Paper Details

Date Published: 1 August 1992
PDF: 8 pages
Opt. Eng. 31(8) doi: 10.1117/12.58843
Published in: Optical Engineering Volume 31, Issue 8
Show Author Affiliations
Jesus D. R. Valera, Heriot-Watt Univ. (United Kingdom)
David Harvey, Heriot-Watt Univ. (United Kingdom)
Julian D. C. Jones, Heriot-Watt Univ. (United Kingdom)


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