optical windows

Windows

Windows are used to admit light into an optical system and to exclude dirt and moisture. When selecting windows you should consider materials, transmission, scattering, wavefront distortion, parallelism and resistance to certain environment. Windows may also be used as coating substrates for use in a wide range of applications.
Optical windows are used to allow optical radiation to pass from one environment to another without allowing other elements of these environments to mix. And it does not change the wavelength distribution of the beam, the transmitted wavefront, nor does it scatter any of the light out of the beam.
Some commonly used materials in windows are BK7, UV Fused silica, Borofloat 33, Pyrex, CaF2,BaF2 ,Other optical glasses from Schott,CDGM.

BK7 Windows
Made from BK7 material, which has transparent range from 330-2100nm. The refractive index is 1.5168 at 587.6nm. The BK7 window has good performance over visible and near IR spectrum for most application.

Specifications:

Material: BK7 grade A optical glass
Dimension Tolerance: +0.0, -0.1mm
Thickness Tolerance: ± 0.1mm
Surface quality: 60/40(Standard), 10/5(High Precision)
Clear Aperture: >85%
Flatness: λ(Standard), λ/10(High Precision) per 25mm@633nm
Parallelism: 1' (Standard), 10