Comparison of Gaussian and Top-Hat Beam Profiles in LIDT Testing

Abstract

The ISO 11254 standard for LIDT tests suggests two possible beam profiles for damage testing. In the case of the Gaussian beam an effective area on the basis of the 1/e² diameter is given, and for a top-hat profile the full diameter is incorporated. To match measurements from test benches working with Gaussian and top-hat laser beams, a comparative test campaign at varying beam diameters is of major interest for an evaluation of analogies or deviations. In order to obtain experimental LIDT, data adequate tests were performed in two testing institutions. An equal set of samples was tested with a Gaussian TEM0,0 as well as with a top-hat beam profile at different beam diameters. This contribution will present results of these investigations at the Nd:YAG wavelength and harmonics in the ns regime.