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Generalized Electrical Substitution Methods and Detectors for Absolute Optical Power Measurements



Solomon I. Woods, Jorge Neira, James E. Proctor, Joseph P. Rice, Nathan Tomlin, Malcolm White, Michelle Stephens, John H. Lehman


We have developed generalized methods for electrical substitution optical measurements, as well as cryogenic detectors which can be used to implement them. The new methods enable measurement of arbitrary periodic waveforms by an electrical substitution radiometer (ESR), which means that spectral and dynamic optical power can be absolutely calibrated directly by a primary standard detector. Cryogenic ESRs are not often used directly by researchers for optical calibrations due to their slow response times and cumbersome operation. We describe two types of ESRs with fast response times, including newly developed cryogenic bolometers with carbon nanotube absorbers, which are manufacturable by standard microfabrication techniques. These detectors have response times near 10 ms, spectral coverage from the ultraviolet to far-infrared, and are ideal for use with generalized electrical substitution. The generalized method and fast detectors greatly expand the range of optical power calibrations which can be made using a wideband primary standard detector, which can shorten calibration chains and improve uncertainties.


electrical substitution, ACR, carbon nanotubes, TES, optical power, power calibration


Woods, S. , Neira, J. , Proctor, J. , Rice, J. , Tomlin, N. , White, M. , Stephens, M. and Lehman, J. (2022), Generalized Electrical Substitution Methods and Detectors for Absolute Optical Power Measurements, Metrologia, [online],, (Accessed June 23, 2024)


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Created June 17, 2022, Updated November 29, 2022