Radial intensity filters using radial birefringent elements

Abstract
A birefringent crystal with a surface curvature ρ provides a radial variation of polarization retardation. One or more such radial birefringent elements in combination with a polarizer form a radial intensity filter (RIF). RIF’s permit the generation of a variety of radial transmittance and reflectance profiles that are useful in resonator and spatial filter applications.