Metalized sapphire windows are created by applying thin layers of chrome, nickel and gold around the edge of a sapphire window. This metalized edge creates a surface that can be soldered or bonded directly into your opto-mechanical assembly allowing you to create a hermetic seal. Hermetically sealed optics is used in a variety of applications ranging from infrared imaging systems to medical devices. Specifications Material: optical sapphire (Al2O3) Diameter tolerance: +0, -0.1mm Thickness tolerance: +/-0.05mm Clear aperture: 90% Surface quality: 80-50 scratches and digs Surface accuracy: 2 lambdas per 25.4mm @ 632.8nm Parallelism: < 3 minutes Coating: AR coating, T > 98% @ 1260-1600nm Metalizing: Chrome, Nickel, and Gold; sputtering method or screen printing method