Patent ID: 9103973
Filing Date: 2015-08-11
Classification: G02B

Abstract:
1. An optical element comprising: a substrate having a planar surface; and a polarization insensitive, high contrast, sub-wavelength grating composed of posts that extend from the planar surface, the grating having at least one region wherein cross-sectional dimensions of the posts or lattice arrangement of the posts are nonperiodically and systematically varied along a direction parallel to the planar surface to control refraction of light transmitted through the optical element, such that a given post does not have a neighboring post with a same cross-sectional dimension as the given post along more than one line, wherein the grating further comprises a thickness that satisfies a condition where t is the thickness of the grating, λ is the wavelength of the light, and n SWG is the effective refractive index of the grating at the wavelength λ.