Complex analysis of laser-induced contamination in high-reflectivity mirrors

Abstract The operation of high-power and high-repetition-rate laser systems is commonly disrupted by the failure of optical components. Optical coatings in vacuum systems accumulate laser-induced contamination (LIC) and are damaged afterward. Currently, only active LIC mitigation methods involving plasma cleaning or oxygen injection in the system are used, which require additional interventions and can disrupt the regular operation. The presented investigation aims to study the multilayer coating design influence on the formation of LIC for dielectric high-reflectivity Bragg mirrors. The manipulation of electric field enhancement on the surface and the material of the last layer revealed that silica tends to accumulate more surface contamination than hafnia materials. Also, the size of the affected area linearly depends on the strength of the E-field at the coating surface. These findings suggest that optimizing coating design – specifically by controlling the E-field distribution and top-layer material – can minimize LIC growth, potentially extending the lifespan of optical components in high-power laser applications, including space and industrial systems.