Analysis of laser intensification by nodular defects in mid-infrared high reflectance coatings

Electric field modeling of nodular defects is performed to investigate the interaction between defective multilayer coatings and Gaussian profile laser beam. Light intensity is significantly enhanced as large as 6 times within the nodular defects. Different geometries of defects irradiated by laser beams at 0 to 40 deg incident laser angles are analyzed. Nodules with large but shallow seeds, or irradiation of 40 deg p-polarized laser beam, tends to produce the greatest enhancement effect.