Practicability of absorption measurements according to ISO/DIS 11551

We present significant differences in absorption measurements at the wavelength 10.6 micrometer and in the near infrared or UV region. This behavior is due to the different materials and their thermal properties. Zinc selenide and copper optics and optics made of various salts have been investigated at 10.6 micrometer. In these cases negligible problems with the measurement and evaluation procedures were observed. At the other wavelengths of 1.06 micrometer and 248 nm the measurements were carried out on BK7 or silica substrates. The evaluation corresponding to the ISO/DIS 11551 was not clear. One reason for this behavior is the low thermal wave velocity, so that the signal will arrive with long delay at the detectors. Furthermore the spatial and the temporal temperature profiles depend on the substrate material and sample geometry our measurements and computer simulations show the influence of the temperature conductivity of the substrate material, the sample thickness and diameter and the distance between the sensors and the laser irradiated area on the obligatory calibration factor.