Brewster Windows are uncoated substrates that are designed to be used at Brewster’s Angle (the angle at which p-polarized light incident on the surface is not reflected). Brewster’s Angle is given by the following formula:
B= tan-1(n)
Here, B is Brewster’s Angle and n is the index of the reflection of the material. At this angle, p-polarization reflectance drops to zero. When used in a laser cavity, a Brewster Window reduces the cavity loss for p-polarized light compared to s-polarized light. The result of preferentially reducing the loss along one polarization axis is that the laser will emit linearly polarized light.
| ATTRIBUTE | SPECIFICATIONS |
| material | UV fused silica |
| minor axis DIAMETER TOLERANCE | +0.0, -0.1mm |
| thickness tolerance | +0.1, -0.1mm |
| parallelism | < 5 arc seconds |
| CLEAR APERTURE | >90% |
| SURFACE QUALITY | 10/5 scratch and dig |
| transmitted wavefront distorsion | λ/10 |
| brewster angle | 55°32′@ 632.8nm |
