Laser-induced damage of intrinsic and extrinsic defects by picosecond pulses on multilayer dielectric coatings for petawatt-class lasers

Abstract

Abstract. We describe a damage testing system and its use in investigating laser-induced optical damage initiated by both intrinsic and extrinsic precursors on multilayer dielectric coatings suitable for use in high-energy, large-aperture petawatt-class lasers. We employ small-area damage test methodologies to evaluate the intrinsic damage resistance of various coatings as a function of deposition methods and coating materials under simulated use conditions. In addition, we demonstrate that damage initiation by raster scanning at lower fluences and growth threshold testing are required to probe the density of extrinsic defects, which will limit large-aperture optics performance. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Comparison of different LIDT testing protocols for PW and multi-PW class high-reflectivity coatings

“…The damage threshold fluence can then be estimated using an extrapolation to zero defect density. Despite its growing popularity in laser damage testing [9][10][11] , the method has not yet been standardized. The main disadvantage of scanning methods is that testing with a relevantly large number of pulses is not feasible, so even a scanning test cannot directly measure the practical threshold of the component and some form of extrapolation is required.…”

Impact of contamination and aging effects on the long-term laser damage resistance of SiO2/HfO2/TiO2 high reflection coatings for 1054 nm

“…Propagating damage tends to be intrinsic, governed by how the laser field interacts directly with the coating molecules. 15 According to the NIF-MEL damage criterion, the LIDT is reached at the fluence at which one or more propagating damage sites occurs, or the fluence at which the number of NP damage sites accumulates to at least 25, whichever fluence is smaller. The 25 or more NP sites are 1% or more of the 2500 sites tested and constitute about 1% or more of the 1 cm 2 coating area tested.…”

A year in review

“…Although it is difficult to draw much insight from citation statistics this soon after 2017 has concluded, it is still interesting to see what paper topics were most cited. According to the Web of Science, three were in the laser damage special section, describing laser damage tests for femtosecond laser coatings, 11 laser-induced damage by picosecond pulses on petawatt-class laser coatings, 12 and laser-based removal of space debris. 13 The active electro-optical sensing special section included top-cited papers on hyperentanglement 14 and deep turbulence wavefront sensing, 15 while papers on anisoplanatic imaging through turbulence 9 (the only top-ten downloaded and cited) and atmospheric turbulence mitigation algorithms 16 from the long-range imaging special section were part of the list.…”