Optical wire-grid polarizers at oblique angles of incidence

Nanotechnology enables the fabrication of wire-grid polarizers ~WGP! in the visible optical region. At oblique angles of incidence, WGP can be used as polarizing beam splitters ~PBS!. As such, they have the advantages of large numerical aperture and high-extinction ratios in both transmission and reflection. Because of these properties, WGP is being explored as PBS replacement in projectors. In this article, we present a complete theoretical investigation of the WGP. Rigorous diffraction theory, exact lowest-order eigenmode effective-media theory, and form birefringence theory are discussed. These theories are compared with experimental measurement of T(u) and R(u) as a function of the polarization state of the input light and as a function of the incident angle u. It is shown that only the rigorous diffraction theory can fit the data for all incident angles. Using diffraction theory we provide a calculation relating the optical properties of the WGP to the physical dimensions of the wire grids. Thus, a framework for optimizing the optical properties of the WGP for various applications and requirements is provided. © 2003 American Institute of Physics. @DOI: 10.1063/1.1559937#