Comparison of Gaussian and top-hat beam profiles in LIDT testing

Abstract

The ISO 11254 standard for LIDT tests suggests two possible spatial beam profiles for damage testing. Accordingly, an equal set of samples was tested with a Gaussian TEM00 as well as with a top-hat beam profile at different beam diameters. It was found that for the investigated HfO2/SiO2 high reflectors there was no threshold dependence on the beam diameter at 355nm. The damage threshold values measured with the Gaussian and the top-hat beam were in good correlation.