Optical window refers to a piece of transparent optical material that allows light into an optical instrument. They are pieces of optical glasses with ground and polished faces that are relatively parallel. Optical windows are applied for protecting fragile optical components inside an equipment, they are adopted to isolate two physical environments while allowing light to pass. A window is usually parallel and is likely to be anti-reflection coated, and may be built into a piece of equipment, such as a vacuum chamber, to allow optical instruments to view inside that equipment.



Material, transmission, scattering, wave front distortion, parallelism and
resistance to certain environments are the factors to be considered about optical
windows' applications.

A wide range of materials could be applied due to
varies demands: BK7, Fused silica, Sapphire, Quartz, Silicon, MgF2, CaF2, ZnSe, etc.

test link