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AR coating

Why Choose an Anti-Reflection Coating?

Due to Fresnel reflection, as light passes from air through an uncoated glass substrate approximately 4% of the light will be reflected at each interface. This results in a total transmission of only 92% of the incident light, which can be extremely detrimental in many applications (Figure 1). Excess reflected light reduces throughput and can lead to laser-induced damage in laser applications. Anti-reflection (AR) coatings are applied to optical surfaces to increase the throughput of a system and reduce hazards caused by reflections that travel backwards through the system and create ghost images. Back reflections also destabilize laser systems by allowing unwanted light to enter the laser cavity. AR coatings are especially important for systems containing multiple transmitting optical elements. Many low-light systems incorporate AR coated optics to allow for efficient use of light.

Figure 1: Fresnel reflections occur at every material interface. Part of every reflected ray will experience additional Fresnel reflection each time it reaches an additional interface1