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Primary Sound Standard Based On Dynamic Fabry Perot Interferometry

Published

Author(s)

Akobuije Chijioke, Richard A. Allen, Steven E. Fick, Benjamin Reschovsky, Jared Strait, Randall P. Wagner

Abstract

We describe an optical sound standard in which the sound pressure is measured by using a high-finesse optical cavity to observe the induced change in the refractive index of the medium (acousto-optic effect). The optical refractive index of a substance varies with density, and for a compressible substance it will therefore vary in time in an acoustic field. To accurately measure the refractive index changes due to acoustic density variations, we enhance the optical phase shifts induced by the index change using a high-finesse optical cavity. By tracking the shift in the optical cavity resonance frequency we sensitively track the shift of the refractive index of the cavity medium and thereby the acoustic pressure in the cavity. We report initial measurements in an acoustic resonator, comparing the pressure indicated by the optical cavity to the pressure indicated by a condenser microphone, at 1 kHz and 2 kHz acoustic frequencies.
Proceedings Title
Proceedings of the 2023 CCM & IMEKO TC16 7th International Conference on Pressure and Vacuum Metrology
Conference Dates
May 15-19, 2023
Conference Location
Washington D.C., DC, US
Conference Title
2023 CCM & IMEKO TC16 7th International Conference on Pressure and Vacuum Metrology

Keywords

sound standard, acoustic-optic, acoustic standard, acoustic resonator, fabry-perot cavity

Citation

Chijioke, A. , Allen, R. , Fick, S. , Reschovsky, B. , Strait, J. and Wagner, R. (2023), Primary Sound Standard Based On Dynamic Fabry Perot Interferometry, Proceedings of the 2023 CCM & IMEKO TC16 7th International Conference on Pressure and Vacuum Metrology, Washington D.C., DC, US, [online], https://doi.org/10.21014/tc16-2023.15, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956554 (Accessed March 21, 2025)

Issues

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Created September 21, 2023, Updated March 3, 2025