High Laser Fluence Ito Coatings Utilizing A Fabry-Perot Thin Film Filter To Reduce Effective Absorption

Laser-induced damage threshold of transparent conductors, such as Indium Tin Oxide (ITO), is limited by their high optical absorption due to free carriers. However, the effective absorption of a transparent conductor thin film can be reduced by an order of magnitude, without changing the electrical characteristics of the film, when placed in a low electric field section of a multilayer coating. A Fabry-Perot thin film interference filter has both high transmittance and low electric field positions, so it is an ideal thin film structure for this application. Although Fabry-Perot interference filters are not known as particularly high laser-induced damage resistant coatings due to their resonant characteristics, a laser-induced damage threshold (LIDT) improvement of up to 8x was observed with this technique compared to single layer ITO coatings fabricated using either radio frequency magnetron sputtering or electron-beam deposition. Additionally, an approximately 4x LIDT improvement for a Fabry-Perot interference filter has been observed by the addition of ITO into the multilayer structure. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement