Brewster window is uncoated substrate used in an optical system at Brewster Angle. It is used to separate the S polarization from the P polarization.
Thin Film Polarizer (TFP's) is used to split a laser beam into two parts with S and P Polarizations. Conversely, TFP's can be used to combine two beams with S and P polarizations. TFP's consist of a coated plate, which is oriented at Brewster's angle with respect to the incoming beam. The thin film coating will enhance the reflectivity of the s-polarized component of the beam, while maintaining high transmission of the p-polarized component.