Room temperature laser power standard using a microfabricated, electrical substitution bolometer

The design and performance of a room temperature electrical substitution radiometer for use as an absolute standard for measuring continuous-wave laser power over a wide range of wavelengths, beam diameters, and powers are described. The standard achieves an accuracy of 0.46% (k = 2) for powers from 10 mW to 100 mW and 0.83% (k = 2) for powers from 1 mW to 10 mW and can accommodate laser beam diameters (1/e²) up to 11 mm and wavelengths from 300 nm to 2 μm. At low power levels, the uncertainty is dominated by sensitivity to fluctuations in the thermal environment. The core of the instrument is a planar, silicon microfabricated bolometer with vertically aligned carbon nanotube absorbers, commercial surface mount thermistors, and an integrated heater. Where possible, commercial electronics and components were used. The performance was validated by comparing it to a National Institute of Standards and Technology primary standard through a transfer standard silicon trap detector and by comparing it to the legacy "C-series" standards in operation at the U.S. Air Force Metrology and Calibration Division (AFMETCAL).