NIM diffuse reflectance scale to super black level (0.0001)

Abstract The realization of the super black level diffuse reflectance scale of the National Institute of Metrology (NIM, China) is presented. Two facilities were used to achieve the reflectance scale under 0 d condition covering 0.0001–1.0 (absolute value), the first one based on the supercontinuum light source was used to realize the diffuse scale in the wavelength range 500 nm–2000 nm, while the other one based on QCL was applied for the mid infrared range from 7.5 μm to 10.6 μm. The relative expanded uncertainty ( k = 2) of the reflectance scale was evaluated to be from 2.3% to 8.4% varying with range and wavelength in visible band to near infrared band while the reflectance is down to 0.0001. In the mid infrared band, the uncertainty of the reflectance scale was up to 8.9% while reflectance is 0.001, and up to 42.6% while reflectance is down to 0.0001. This low reflectance level scale can meet the calibration requirement of super black material or system such as carbon nanotube or blackbody.