Geometry-dependent laser damage resistance of fused silica metastructures: a multiphysics simulation investigation

Their opto-thermo-mechanical response fundamentally constrains the reliability of dielectric metasurfaces under high-power laser irradiation. In this study, we systematically investigate the thermomechanical behavior of cylindrical fused silica metastructures under nanosecond pulsed laser irradiation using a fully coupled multiphysics finite element model. Our results reveal that the maximum temperature exhibits a nonlinear oscillatory dependence on the cylinder height, attributed to Mie-type optical resonances, while the maximum thermal stress decays with increasing height in accordance with Saint-Venant’s principle. These findings provide a theoretical basis for designing laser-resistant metasurfaces through geometric optimization.