Contribution of angle-dependent light penetration to electric-field enhancement at nodules in optical coatings.

The influence of angle-dependent light penetration on electric-field intensity (EFI) enhancement at nodules was investigated in this Letter. An experiment consisting of 3D finite-difference time-domain simulations was conducted on two types of polarizers that prevent light penetration at a low and a high incident angular range (IAR). The EFI at the focal point region is six times lower, and the laser damage resistance is three times higher in the polarizer blocking light penetration in a high IAR. These results reveal for the first time, to the best of our knowledge, that light penetration at a high IAR, rather than at a low IAR, contributes to EFI enhancement at the focal region of the nodules. Our findings may provide useful guidance in selecting optimal designs to suppress EFI enhancement at nodules in multilayer coatings.