Automated test station for laser-induced damage threshold measurements according to ISO 21254-1,2,3,4 standards

ABSTRACT An automated test station to measure the laser-induced damage threshold (LID T) according to ISO 21254-1,2,3 ,4:2011 standards is presented. The laser is a single longitudinal mode, 500 mJ, 6 ns, Q-switched, 10 Hz, linearly polarized, 1064 nm laser, with 2-nd and 3-rd harmonic capabilities. The machine is able to operate the S-on-1 test (S = 500), or the Type 2 endurance (durability) test. The main blocks of the station are described, emphasizing some original solutions. Preliminary results of LIDT measurements using the S-on-1 test on several coatings and on uncoated fused silica substrates with various degrees of roughness are also presented. Keywords : LIDT, automated test station, S-on-1 test, Nd:YAG laser 1. INTRODUCTION Within the context of the new international research infrastructure, the Extreme Light Infrastructure - Nuclear Physics facility (ELI-NP), to be implemented in Bu charest, Romania during the next couple of years, a two-arm very high-power laser system will be developed, delivering an estimated 10 PW peak pulse power on each arm. As a result of the multiple technical challenges, foreseen or yet unknown, several smaller, independent projects were started. This paper reports an automated test station for laser-induced damage threshold (LIDT) measurements, aimed to implement the recommendations of the LIDT-dedicated ISO 21254-1,2,3,4:2011 standards