Broadband radiometry with spectrally selective detectors

A spectrally selective optical-radiation detector can be normalized to an equivalent detector having unique values for its average responsivity R¯ and its cut-on and cutoff wavelengths λ1 and λ2 It is shown that the radiant power of any source that is described by a second-degree polynomial can be determined exactly between limits λ1 and λ2 Calculations were made for several real detectors and Planckian radiators at several temperatures to demonstrate the low errors inherent in this scheme.