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arXiv · 1609.05861

All-Optical Detection of Acoustic Pressure Waves with applications in Photo-Acoustic Spectroscopy

Philip G. Westergaard·Mikael Lassen
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Abstract

An all-optical detection method for the detection of acoustic pressure waves is demonstrated. The detection system is based on a stripped (bare) single-mode fiber. The fiber vibrates as a standard cantilever and the optical output from the fiber is imaged to a displacement-sensitive optical detector. The absence of a conventional microphone makes the demonstrated system less susceptible to the effects that a hazardous environment might have on the sensor. The sensor is also useful for measurements in high temperature (above $200^{\circ}$C) environments where conventional microphones will not operate. The proof-of-concept of the all-optical detection method is demonstrated by detecting sound waves generated by the photo-acoustic effect of NO$_2$ excited by a 455 nm LED, where a detection sensitivity of approximately 50 ppm was achieved.

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Philip G. Westergaard, Mikael Lassen. 2016-09-15. All-Optical Detection of Acoustic Pressure Waves with applications in Photo-Acoustic Spectroscopy. https://doi.org/10.1364/ao.55.008266

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