THE NIST HIGH-ACCURACY SCALE FOR ABSOLUTE SPECTRAL RESPONSE FROM 406 NM TO 920 NM

We describe how the National Institute of Standards and Technology obt ains a scale of absolute spectral response from 406 nm to 920 nm. This scale of absolute spectral response is based solely on detector measu rements traceable to the NIST High Accuracy Cryogenic Radiometer (HACR ). Silicon photodiode light-trapping detectors are used to transfer op tical power measurements from the HACR to a monochromator-based facili ty where routine measurements are performed. The transfer also involve s modeling the quantum efficiency (QE) of the silicon photodiode light -trapping detectors. We describe our planned quality system for these measurements that follows ANSI/NCSL Z540-1-1994. A summary of current NIST capabilities based on these measurements is also given.