Calibration procedures for a 10.6-μm laser calorimeter

The paper presents the theoretical background of laser calorimetry as a method to investigate the absorptance of optical components, according to the recently adopted ISO Standard 11 551. An experimental set-up for optical absorption measurements, including a cw CO2 laser and a calorimetric chamber, is presented. The calibration of the laser calorimetric set-up is also described. The calibration involved several steps: laser power calibration, evaluation of chamber sensitivity, electrical calibration using electrically heated samples and optical calibration utilizing 100% absorptance samples. There were measured the conversion factors for the laser power and for the sample temperature; there were calculated over-all correction factors for the different substrates and they could be placed within +/- 4% around their mean value.