US Patent 7221515 Optical diffraction element

An optical diffraction element (1) comprises a diffraction layer (4) which is divided into diffraction strips (6) alternating with intermediate strips (8). The diffraction strips comprise nano-elements (10) which are aligned in one direction and absorb radiation (b) which is linearly polarized in this direction. The diffraction element may be a linear or two-dimensional grating (1) or a Fresnel lens (160). The polarization-sensitive grating can be used in optical systems in which only radiation with a specific polarization direction should be diffracted, or in an optical record carrier to allow reading of an information structure with high spatial frequencies.