S on 1 testing of AR and HR designs at 1064 nm

Abstract

In this paper, we present test results and involved procedures of a comprehensive test campaign for S on 1 testing of laser optics with large test areas allowing the generation of a profound test database for further analysis. This database will serve as a starting point for an empirical study of the lifetime of laser optics, which will be discussed in companion paper somewhere in these proceedings [1]*. The optics are designed to operate as anti-reflective or high-reflective components at the respective test wavelengths for 0° angle-of-incidence. Both, coatings and substrates of 2.0 inch diameter are produced from the same batches to be as identical as possible. There were two different coating technologies used, e-beam and IAD e-beam, to explore a possible effect of the coating process on the long term laser irradiation behavior. The laser damage test bench is operated with a laser source delivering laser pulses in a single longitudinal mode at a repetition frequency of 100 Hz. The beam profile is of a Gaussian-shape and of high spatial quality at the fundamental Nd:YAG laser wavelength with a pulse duration of 3.5 ns at 1064 nm. Typical beam diameters on the samples were 400 μm, and usually more than 500 test sites are irradiated in one test to achieve statistical significance. The laser test procedure itself is adapted from the ISO standard 11254-2 for multiple pulse irradiations, and the LIDT evaluation is done accordingly.