Optical detection of ultrasound with a phase-modulated Michelson interferometer

A phase-modulated Michelson interferometer for optical detection for ultrasound is described. The operating point of the interferometer is kept to the minimum intensity of the interference pattern. This scheme allows the use of a high power laser to improve the sensitivity without a photodiode satur...

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Bibliographic Details
Published in:Review of scientific instruments 1999-11, Vol.70 (11), p.4275-4278
Main Authors: Nakano, Hidetoshi, Matsuda, Youichi, Nagai, Satoshi
Format: Article
Language:English
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Summary:A phase-modulated Michelson interferometer for optical detection for ultrasound is described. The operating point of the interferometer is kept to the minimum intensity of the interference pattern. This scheme allows the use of a high power laser to improve the sensitivity without a photodiode saturation. Ultrasonic displacement amplitudes as small as 10 pm can be detected when the maximum intensity on the photodiode is 100 mW. The detected root-mean-square noise is twice as much as the theoretical prediction of 3×10 −16   m / Hz . The ultrasonic wave forms excited with a transducer and a pulsed laser in a Si sample are presented.
ISSN:0034-6748
1089-7623
DOI:10.1063/1.1150066