Brewster windows operate at an angle of incidence equal to the ‘Brewster angle’ which is 67.4 degrees for ZnSe at 10.6mm. In order to present a square profile to the incident beam, they are about 2.5 times longer than their width. They fully transmit linearly polarized light in the P-plane and reflect about 50% of the S-plane component. Consequently, they can be used to enhance (‘clean-up’) the polarization or by rotating it about the beam axis, they can be used as an attenuator. Coated versions enhance the reflectance of the S-component but at the expense of restricting the power. Usually, Brewster windows are used in pairs.
- Wedged to between 3 and 5 arcminutes in order to overcome multiple interference
- Coated or uncoated versions and many sizes available
- Also available in matched wedge pairs
The following Brewster windows are currently available. Others may be available upon request.