Photonic Standards For Acoustics

This project seeks to advance the development and implementation of new, better, acoustical calibration methods based on optical sensing: (1) Use of laser Doppler vibrometer (LDV) measurements of microphone volume velocity to achieve improved reciprocity-derived secondary calibrations; (2) Use of optical measurements of refractive index change to measure sound pressure with a refractive index sound standard (RISS). The LDV system will improve the uncertainties and simplify the procedure for secondary microphone calibrations done at the standard frequencies of 250 Hz and 1 kHz, resulting in time and cost savings. The refractive index sound pressure measurement will provide an independent traceability path, is expected to allow calibration of a wider range of devices at a wider range of frequencies and can provide traceability to a quantum standard.

Publications:

• Wagner, R. , Allen, R. and Dong, Q. (2021), Laser-based comparison calibration of laboratory standard microphones, Journal of the Acoustical Society of America Express Letters, [online], https://doi.org/10.1121/10.0005919, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932083
• Chijioke, A. , Allen, R. , Fick, S. , Long, D. , Reschovsky, B. , Strait, J. and Wagner, R. (2023), Optical-cavity-based primary sound standard, 28th International Congress on Sound and Vibration 2022 (ICSV28), Singapore, SG, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934484
• 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

Patents:

• Patent US 11,956,601B2 “INTERFEROMETRIC MICROPHONE CALIBRATOR AND COMPARISON CALIBRATING A MICROPHONE” (Allen, Wagner)

News highlights:

• Testing 1-2: New Laser-Based Microphone Calibration Measures Up
• Now Hear This!