Saint-Gobain Crystals has introduced a new highly reflective coating, specifically intended for excimer laser-based scanning applications in which high reflectivity over a wide range of incident angles and broad wavelength bandwidth is required.
The new Alpine Research Optics-brand thin film is a UV-enhanced aluminum coating that delivers more than 95 per cent reflectivity at 193nm (at 45° incidence), while also offering an average reflectivity of greater than 85 per cent over the 400nm to 1,000nm spectral range. The metal/dielectric hybrid coating also delivers more than 90 per cent reflectivity at 193nm over an angle of incidence range of ±10°, which is virtually impossible to accomplish with an all-dielectric design.
The primary application for this high-reflectance coating is in excimer laser-based systems used for ophthalmic procedures, such as LASIK and PRK. In these instruments, the scan mirror for the excimer laser beam may also be part of the optical path for a visual inspection system or near infrared camera system, so high reflectance in both spectral regions is required.
Saint-Gobain Crystals supplies this coating on a wide variety of substrates suitable for galvanometer scanners. These include rectangular fused silica substrates with chamfered edges. Other materials and substrate shapes are available upon request.