Windows and wedges
Windows and wedges are elements from group of plane optical elements. They are used in optical systems not as lenses or mirrors. Beam is reflected or goes through such elements instead of being converged.
Optical windows are used mainly for protection of optical systems against dust and damage. They are also used in optics for separation of different environments. Specification for windows is the same as for plane parallel plates. Surfaces of the windows which are used in non-polarized light can be coated by suitable antireflection coatings to decrease reflection losses.
Optical wedges are used in optical systems as beam steering elements.
Wedges are often used as compensators, because by rotating them slightly it is possible to change the optical path lengths easily. It is possible in all the cases when only one optical surface should operate, and reflection from the second one is not desired.
Both – windows and wedges, are usually made of typical optical materials like BK7 or fused silica. On request we can also coat elements with required thin film coatings like AR, which actually is the most often used.