A new power meter with a sensitive micro-calorimeter has been developed to measure the absolute power of FIR laser. Using this power meter, a calibration of a Scientech power and energy meter of 36 series has been carried out for 337 μm wavelength.
S. Okajima, S. Okajima,
"Development of FIR power meter", Proc. SPIE 1514, 15th International Conference on Infrared and Millimeter Waves, 151438 (1 December 1990); doi: 10.1117/12.2301526; https://doi.org/10.1117/12.2301526