The base of Brewster windows is not coated, it is usually used as a polarizer. When window is placed at the Brewster angle, the P polarization component of the beam will pass through the window without loss, and most of the S polarization component will be reflected by the Brewster window, which is very suitable for use in the laser cavity.
Brewster Angle @633nm: 55.32°
Dimension Tolerance: 0.0/-0.1mm
Thickness Tolerance: ±0.1mm
Clear Aperture: ≥90%
Surface Quality: 20/10