Design of polarization splitting devices with ideal transmission and anisotropy considerations

Abstract

In this paper, we introduce the generalized design of nonmagnetic homogeneous polarization splitting devices (polarization deflector/lateral shifter) based on linear area-preserving transformations for an arbitrary incident angle. Also, by employing the Brewster angle condition, we derive a quadratic equation for principal values of the permittivity tensor that leads to the reflectionless splitting of two orthogonal polarizations for a normally impinging wave. The minimum in-plane anisotropy condition is then derived. The Brewster angle method offers significantly less anisotropy compared with the transformation optical design for larger deflection angles/lateral shifts in the normal incidence case. Finally, we show that, by using a uniaxial material (zero in-plane anisotropy), we can achieve similar functionality in the case of an obliquely incident wave. The proposed devices can separate the polarizations of the incident wave by creating a desired angle or lateral shift between TE and TM polarizations. The functionality of the proposed designs is confirmed by the commercial finite-element-based software COMSOL Multiphysics.