Design of laser antireflection coating on substrate with subsurface damage

Subsurface damage (SSD) of optical material is a focal point of research in laser optical field. The existence of SSD of substrates would change the properties of thin film, and the influence of the surface damage in substrates is essential to ansider during the design, manufacture of high precision low loss laser antireflection coating. Physical properties of SSD were studied. And the physical thickness and refractive index gradient of SSD could be retrieved by the spectroscopic ellipsometry of substrate surface. Then the effect of them on reflection spectrum of antireflection coating was obtained by calculation. The depth of SSD affects the reflection spectrum periodically. At last, with depth and gradient of SSD taken into account, the design of laser antireflection coating was revised theoretically, and the numerical experiment shows that the design is possible to realize zero-reflection at 633 nm.