Re-evaluation of spectrophotometric standard reference materials for additional geometries and wavelengths

Two types of mirrors and a glass are used as Standard Reference Materials to calibrate the specular reflectance scales of optical systems. While calibrations of these materials are routinely performed using the 6 degrees/6 degrees geometry, there has been an increased interest in the optical radiation measurement community for additional bidirectional geometries such as 30 degrees/30 degrees and 45 degrees/45 degrees. This paper reports the results of specular reflectance measurements of first surface aluminum and gold mirrors and polished black glass at wavelengths from 250 nm to 2250 nm. Supplemental measurements of wavelength standards are included to provide a comprehensive overview of the standards available for calibrating spectrophotometers.