Explore anti-reflective coating technology: How AR thin films cut Fresnel reflections, boost transmission, and reduce ghosting. It begins by outlining the physics of thin-film interference and refractive index matching, establishing the. The predominant method for causing anti-reflection of an optic is by depositing a layer or several layers of compounds onto the surface of the optic. What Are Anti-Reflection Coatings? Anti-reflection coatings are extremely thin films applied. An anti-reflection coating (AR coating) is a dielectric thin-film coating applied to an optical surface to reduce the reflectance (also often called reflectivity) of that surface due to Fresnel reflections — at least in a certain wavelength range.