Axial force radiometer for primary standard laser power measurements using photon momentum

Published

January 11, 2021

Author(s)

Paul Williams, Kyle Rogers, Joshua A. Hadler, Alexandra Artusio-Glimpse, John Lehman

Abstract

We have fully demonstrated operation of a new photon momentum radiometer for measuring laser power levels above 1 kW by use of radiation pressure. The "axial" design allows the input and output laser beams to remain collinear and the force sensing can be carried out with any analytical balance having a vertical sensing direction and suitable performance specifications. The design also includes a parasitic photodiode power measurement that is calibrated in situ by the radiation pressure- based power. This permits a higher bandwidth of measurement limited only by the photodiode bandwidth, rather than that of the force balance. Uncertainty contributions are fully discussed yielding a relative expanded uncertainty of 2.1 % for 1-2 kW and 1.2 % above 2 kW (for laboratory environmental conditions). We perform a direct comparison between this new power meter and the existing primary standard Radiation Pressure Power Meter. We find the two techniques agree within 0.5 % from 1- 10 kW of cw optical power. This disagreement is well-explained by the combined uncertainties of the two techniques.

Citation

Metrologia

Pub Type

Journals

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Keywords

Radiation pressure, photon momentum, radiometry, laser power, high power laser

Citation

Williams, P. , Rogers, K. , Hadler, J. , Artusio-Glimpse, A. and Lehman, J. (2021), Axial force radiometer for primary standard laser power measurements using photon momentum, Metrologia, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=930204 (Accessed May 9, 2026)

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