Broad-Band Polarizing Light Beam Splitter Based on a Multilayer Thin-Film Coating

A polarizing light beam splitter is created in the form of two Dove prisms of BK7 glass with a multilayer thin-fi lm coating made of two periodic substructures between them. The number of layers of Nb2O5 and SiO2 in each structure and their thicknesses are chosen to ensure that they reflect s-polarized and transmit p-polarized components of the incident light over the entire specified working spectral range of the splitter. This is achieved by partial overlap and supplementation by one another of photon band-gap structures of the corresponding structures at the Brewster angle. For a full divergence angle of the input light beam of up to 10o, the manufactured polarizing splitter provides a degree of polarization of 0.99 over the working wavelength range of 400–800 nm. Since the material for making the polarizing splitter is optical glass, the size of the splitters of this design is limited only by the working volume of the vacuum chambers used to deposit the optical coatings.