Optical windows According to custom design to manufacture infrared windows, UV fused silica windows, CaF2 windows, ZnSe windows, Si windows, etc. Material: flint glass, UV fused silica, infrared fuses silica, CaF2, Ge, ZnSe, Si, etc. Diameter: 4mm-- 100mm Parallelism: ¦Ë/10 Surface quality: 40/20 Clear Aperture: 90% Coating: custom design