Quarter wave plate polarizer with two phase-shifting portions

摘要

A right circular cylindrical body of an isotropic dielectric such as a cross-linked styrene copolymer, has respective pluralities of mutually parallel grooves formed in its axial end faces, spaced apart by an intermediate portion whose dimension c is a half wavelength. The axial lengths a, b of the grooves are such that when a wave passes through the body, a quarter wavelength phase difference is produced between a component of a wave having its E-vector parallel to the grooves and a component of the wave having its E-vector orthogonal to the grooves. Alternatively the plate may consist of two or more discrete bodies whose grooves are dimensioned to produce a total differential phase shift of one quarter wavelength.

主权项

1. A quarter wave plate, comprising:
at least one body of dielectric material, said at least one body having respective first and second end faces on opposite sides thereof, and including i); the first and second end faces each having a respective reflection coefficient, said at least one body including: a respective first portion for providing a phase shift between first and second orthogonal components of an electromagnetic wave traversing the plate, and including a respectiveplurality of first number of parallel grooves extending inwardly of said respective first end face; ii) a respective second portion for providing a phase shift between the first and second orthogonal components of the electromagnetic wave, and including a respectiveplurality of second number of parallel grooves extending inwardly of said respective second end face and aligned with the grooves of said respectiveplurality of first number ofparallel grooves; and iii) a respective third portion defined between said respective first and second portions, wherein respective depths of the plurality of first and second parallel grooves are configured to produce the phase shifts of an odd integer multiple of quarter wavelengths between said first and second orthogonal components of the electromagnetic wave traversing the plate, the first component having an E-vector parallel to the plurality of first and second parallel grooves, and the second component having an E-vector perpendicular to the plurality of first and second parallel grooves, wherein the dielectric material has a relative dielectric constant less than 5, and wherein a length of the third portion is selected to differ from a half-wavelength by an amount to adjust the respective reflection coefficient at the first and second end faces.