High efficiency homogeneous polarization converter

Abstract

A polarization converter polarizes an incident light beam having a first component with a first plane of polarization and a second component with a second plane of polarization orthogonal to the first plane. The polarization converter comprises a planar matrix for concentrating and collimating the incident light beam; a polarizer parallel to the planar matrix for refracting the first component and reflecting the second component; quarter-wave retarding means, parallel to the planar matrix and disposed between the planar matrix and the polarizer, for delaying the second component one-quarter wavelength relative to that of the first component; and reflection means, between the quarter-wave retarding means and the planar matrix, for reflecting the second component back through the quarter-wave retarder. The planar matrix may include on a top surface an array of first lenses and on a bottom surface an array of second lenses. The first and second lenses operate jointly to concentrate and collimate the incident light beam. The polarizer divides the concentrated light beam based on their planes of polarization into the first and second components, thereby enabling the quarter-wave retarder and the reflection means to orient only the second component to match the orientation of the first component.