NIM diffuse reflectance scale to super black level (0.0001)

• Published in: Metrologia 2025-02, Vol.62 (1)
• Main Authors: Feng, Guojin, Zheng, Chundi, Gan, Haiyong, Lin, Yandong, Wu, Houping, Sun, Ruoduan, Zhang, Qiaoxiang, He, Yingwei, Ma, Yuxuan
• Format: Article
• Language: English
• Subjects: calibration; carbon nanotube integrating sphere; rotate-aperture method; super black reflectance standard
• ISSN: 0026-1394; 1681-7575
• DOI: 10.1088/1681-7575/ad96c0

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, the first one based on the supercontinuum light source was used to realize the diffuse scale in the wavelength range 500 nm to 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(coverage factor k = 2) of the reflectance scale was evaluated to be from 2.2 % 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 8.8% while reflectance is 0.001, and up to 42.4% 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.