Patent ID: 6219478
Filing Date: 2001-04-17
Classification: G02B,H01S

Abstract:
A light wave diffraction device formed of:a layer in which light waves can propagate,a reflective structure or surface arranged on one lower face of said layer, anda diffraction grating or equivalent diffraction means arranged at one face of said layer or within the latter in the form of a periodic modulation of its refractive index; wherein, for an incident wave to be diffracted by this device and having a given wavelength .lambda. and a predetermined angle of incidence on said layer defined relative to the direction perpendicular to this layer, the mean height of said layer substantially satisfies the resonance condition for a leaky mode of the incident wave refracted in this layer, and wherein said grating or equivalent means has/have a spatial period whose value is determined to diffract said incident wave essentially along the first negative order of diffraction and at an angle of diffraction having a value different from a value substantially equal to that of said angle of incidence.