Optical sound pressure measurement using Fabry-Pérot cavity for primary acoustic standards

Fuente: arXiv
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Bibliographic Details
Main Authors: Hirano, Koto, Kokuyama, Wataru, Inaba, Hajime, Okubo, Sho, Shimoda, Tomofumi, Takahashi, Hironobu, Yamada, Keisuke, Nozato, Hideaki
Format: Preprint
Published: 2025
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author Hirano, Koto
Kokuyama, Wataru
Inaba, Hajime
Okubo, Sho
Shimoda, Tomofumi
Takahashi, Hironobu
Yamada, Keisuke
Nozato, Hideaki
author_facet Hirano, Koto
Kokuyama, Wataru
Inaba, Hajime
Okubo, Sho
Shimoda, Tomofumi
Takahashi, Hironobu
Yamada, Keisuke
Nozato, Hideaki
contents Optical sound pressure measurement is a promising technology to establish primary acoustic standards without reliance on specific types of microphones. We developed a precision optical sound pressure measurement system by combining a Fabry-Pérot optical cavity, a phase-stabilized optical frequency comb, and a custom-made phasemeter. The optical cavity detects changes in the air's refractive index induced by sound waves as changes in its resonance frequency. A continuous-wave laser frequency is stabilized at the resonance, and the frequency comb detects the changes in the laser frequency. The frequency changes are measured with high sensitivity and accuracy using a phasemeter that we developed. The sound pressures measured by this system agreed with the measurement value obtained using a reference microphone within 5% at sound pressure levels of 78 dB and 84 dB, within a frequency range of 100 Hz to 1 kHz. A systematic deviation of 2.6% was observed, with the optical system yielding higher values than the microphone. To identify the cause of this deviation, we performed vibration displacement measurements of the cavity mirrors and finite element analysis, which revealed that fluctuations in the optical path length due to insufficient fixation of the mirrors were responsible.
format Preprint
id arxiv_https___arxiv_org_abs_2509_10480
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optical sound pressure measurement using Fabry-Pérot cavity for primary acoustic standards
Hirano, Koto
Kokuyama, Wataru
Inaba, Hajime
Okubo, Sho
Shimoda, Tomofumi
Takahashi, Hironobu
Yamada, Keisuke
Nozato, Hideaki
Instrumentation and Detectors
Optical sound pressure measurement is a promising technology to establish primary acoustic standards without reliance on specific types of microphones. We developed a precision optical sound pressure measurement system by combining a Fabry-Pérot optical cavity, a phase-stabilized optical frequency comb, and a custom-made phasemeter. The optical cavity detects changes in the air's refractive index induced by sound waves as changes in its resonance frequency. A continuous-wave laser frequency is stabilized at the resonance, and the frequency comb detects the changes in the laser frequency. The frequency changes are measured with high sensitivity and accuracy using a phasemeter that we developed. The sound pressures measured by this system agreed with the measurement value obtained using a reference microphone within 5% at sound pressure levels of 78 dB and 84 dB, within a frequency range of 100 Hz to 1 kHz. A systematic deviation of 2.6% was observed, with the optical system yielding higher values than the microphone. To identify the cause of this deviation, we performed vibration displacement measurements of the cavity mirrors and finite element analysis, which revealed that fluctuations in the optical path length due to insufficient fixation of the mirrors were responsible.
title Optical sound pressure measurement using Fabry-Pérot cavity for primary acoustic standards
topic Instrumentation and Detectors
url https://arxiv.org/abs/2509.10480