Silicon photodiode absolute spectral response self-calibration using a filtered tungsten source.

A method of extending the silicon photodiode absolute spectral response self-calibration techniques to non-laser wavelengths using a tungsten source filtered with narrow well-characterized interference filters is described. Results are presented for comparisons of two photodiode self-calibrated with a laser source and for comparisons of two photodiodes self-calibrated with the filtered tungsten source. Results of the photodiode self-calibration with filtered tungsten radiation were verified by comparisons with a spectrally flat pyroelectric radiometer calibrated in terms of the self-calibration of photodiodes at the He-Ne laser wavelength. These data show that the method can be used to establish an absolute spectral response scale, from 0.400 to 0.800 microm, with an uncertainty of better than +/-1.0%. The scale realized by the self-calibration method is independent of lamp standards and blackbody detectors. The method can be used in any moderately equipped laboratory.