Stolz Christopher J, Feigenbaum Eyal
Appl Opt. 2020 Feb 10;59(5):A20-A25. doi: 10.1364/AO.59.000A20.
Electric field enhancement due to nodular defects within quarter-wave optical thickness multilayer mirrors is impacted by the inclusion diameter, inclusion depth, inclusion composition, nodular shape, multilayer angular bandwidth, multilayer coating materials, number of layers, angle of incidence, and polarization. In this modeling study, the electric field enhancement for surface inclusions with diameters up to 2 µm irradiated at 1064 nm at either normal or 45 deg incidence is calculated for high refractive index materials over a refractive index range of 1.7-2.3 for oxide materials commonly used in the near infrared. The thicknesses of the multilayer mirror thin films are determined for each high refractive index material by a requirement to meet a 99.5% reflection. The refractive index was found to have a significant impact on the electric field enhancement, which may offer some insight into the optimal material choice to produce high laser damage threshold mirrors.
四分之一波长光学厚度多层反射镜内的结节状缺陷所导致的电场增强，会受到夹杂物直径、夹杂物深度、夹杂物成分、结节形状、多层角带宽、多层涂层材料、层数、入射角和偏振的影响。在这项建模研究中，针对在近红外中常用的氧化物材料，在1.7 - 2.3的折射率范围内的高折射率材料，计算了直径达2 µm的表面夹杂物在1064 nm波长下垂直或45度入射角照射时的电场增强。通过满足99.5%反射率的要求，为每种高折射率材料确定多层反射镜薄膜的厚度。发现折射率对电场增强有显著影响，这可能为选择生产高激光损伤阈值反射镜的最佳材料提供一些见解。
