Method for characterization of filter radiometers

We have developed a new method for characterizing the irradiance responsivi ty of filter radiometers. The method is based on a spatially uniform, known irradiance, generated by combining several identical laser beams. The meas urement setup and the experimental demonstration at one wavelength are pres ented. The diffraction correction related to the generated irradiance is st udied experimentally. The uncertainty analysis of the method indicates a re lative standard uncertainty of 1 x 10(-3). The results with the new method are compared with the characterization measurements based on our present sp ectral-irradiance scale. The results have a relative deviation of 1 x 10(-3 ), which is well within the combined standard uncertainty of the comparison . (C) 1999 Optical Society of America.