A dielectric mirror is an optical component formed by the alternating stacking of multiple dielectric layers. Its core function is to enhance the reflectivity of light at specific wavelengths, which is the opposite of the anti-reflective effect of anti-reflection coatings. Hence, it is also referred to as a "high-reflection coating." It is constructed by alternately depositing two dielectric materials with different refractive indices (n1 and n2, n1≠n2), with each layer typically having a thickness of one-quarter of the target wavelength. High reflectivity is achieved through the interference effect of light.
I. Core Characteristics and Sensitive Parameters
Incident Angle Sensitivity: Unless otherwise specified, the default incident angle is 45°, and it is relatively sensitive to changes in the incident angle.
Polarization Dependence: The reflectivity for P-polarized light (parallel to the plane of incidence) is lower than that for S-polarized light (perpendicular to the plane of incidence), and the reflection bandwidth is narrower.
High Damage Threshold: The multilayer dielectric film structure makes the mirror less prone to damage, capable of withstanding continuous high-power laser irradiation, and supports cleaning and maintenance.