Gallium phosphide (GaP) as a standard ultraviolet index detector: response comparison and measurements

Abstract One of the significant metrics that has lately emerged as a result of climate change is the Ultraviolet Index (UVI). In this work, the authors established a standardized reference UVI radiometer at NIS, Egypt, and discussed the performance to cover the actual actinic spectrum. Selective commercial UVI radiometers based on the proposed detector's responsivity and spectral mismatch were compared to the standardized reference UVI radiometer. The result indicated that the established detector response covers the entire UV actinic spectrum (280–405 nm). Besides, the standardized reference UVI radiometer has the least spectrum mismatch value with the (CIE) spectral response, according to a comparison between it and the other detectors that have been evaluated. Furthermore, it has the highest occupied area under the CIE spectral response curve, which is about 73.8%, and has about 12% better performance. These findings support to use of the established detector as a reference standard for detecting UVI at the radiometry lab at NIS Egypt.