Sapphire Windows Sapphire Windows are manufactured from single crystal sapphire, making them ideal for demanding applications (such as laser systems) because of their extreme surface hardness, high thermal conductivity, high dielectric constant and resistance to common chemical acids and alkalis. Sapphire is the second hardest crystal next to diamonds and, because of their structural strength, sapphire windows can be made much thinner than other common dielectric windows with improved transmittance. Chemically, sapphire is single crystal aluminum oxide (Al2O3), and is useful in a transmission range from 0.2 - 5.5µm. We can supply professional customized service in time and provide cooperation and support of new product development and technology appliance. Specification of Sapphire Windows Refractive index(nd) 1.768 Coefficient of dispersion (Vd) 72.2 Density(g/cm3) 3.97 TCE(μm/m℃) 5.3 Soften Temperature(℃) 2000 Knoop hardness(kg/mm2) 2200