Design of a binary grating with subwavelength features that acts as a polarizing beam splitter

A binary diffractive optical element, acting as a polarizing beam splitter, is proposed and analyzed. It behaves like a transmissive blazed grating, w orking on the first or the second diffraction order, depending on the polar ization state of the incident radiation. The grating-phase profile required for both polarization states is obtained by means of suitably sized subwav elength groups etched in an isotropic dielectric medium. A rigorous electro magnetic analysis of the grating is presented, and numerical results concer ning its performances in terms of diffraction efficiency as well as frequen cy and angular bandwidths are provided. (C) 2001 Optical Society of America .