Large-flux-ratio linearity measurements on Si photodiodes

Most methods for testing the linearity of detectors use steps which are small compared with the total linear range of the detector. The uncertainties of each small step accumulate if large flux ratios are considered. For testing the linearity of Si photodiodes for large flux ratios, such a ratio was generated by reflecting a laser beam at two fused quartz surfaces. The ratio between the twice reflected and the incident flux was calculated from the refractive index. Measurements on one Si photodiode are reported.