CHARACTERIZATION OF PHOTODIODES IN THE UV AND VISIBLE SPECTRAL REGION-BASED ON CRYOGENIC RADIOMETRY

Different types of photodiode have been characterized with respect to uniformity, linearity, stability of responsivity and temperature coefficient at several wavelengths between 257 nm and 799 nm based on cryogenic radiometry and intensity stabilized lasers. The Hamamatsu S1337 photodiode was found to be the best suited for use as a high accuracy transfer standard for both the visible and UV spectral regions. For low-level radiant power measurement, this kind of photodiode can be calibrated via a cryogenic radiometer with a total uncertainty as low as +/- 0,02 % in the visible and +/- 0.25 % in the UV.