ISP Optics Infrared Brewster Windows are uncoated germanium (Ge) and zinc selenide (ZnSe) windows used to separate p-polarized and s-polarized light. When positioned at Brewster’s angle, 67.4° at 10.6µm for ZnSe and 76.0° at 10.6µm for Ge, the p-polarized component of light is transmitted with no reflection losses. The s-polarized component of light is reflected through Fresnel reflections; for ZnSe, approximately 50% of s-polarized light is reflected, while Ge with a higher refractive index reflects close to 87%. ISP Optics Infrared Brewster Windows are designed to provide a square input aperture when used at Brewster’s angle and can be used solo or in pairs to act as polarizers, analyzers, attenuators, or isolators within an optical system.
Note: Special care should be taken when handling Zinc Selenide as it is a toxic material. Always wear rubber or plastic gloves to avoid risk of contamination.