LBTEK Metallic Coating Concave Mirrors use a Borofloat 33 substrate, and their concave surface is coated with a Metallic Coating (UV-enhanced aluminum coating with a protective layer). This reflective coating has high Reflectance (Ravg > 90%) over the 250 nm–600 nm wavelength range, making it highly suitable to collimate, focus, and image UV-band beams without introducing chromatic aberration. Metallic Coatings are easily oxidized, discolored, or peeled off in high-humidity environments. The SiO2 protective layer isolates the Metallic Coating from direct contact with air, preventing oxidation of the Metallic Coating from affecting optical performance. Currently, LBTEK's UV-enhanced aluminum-coated Concave Mirrors are available in three sizes (Ø12.7 mm/Ø25.4 mm/Ø50.8 mm) and seven different Focal Length (f) values (-25 mm to -500 mm). In addition to standard products, LBTEK also provides custom solution options for size, Focal Length (f), and wavelength range. If needed, please contact LBTEK technical support.