Patent ID: 8547638
Filing Date: 2013-10-01
Classification: G02B

Abstract:
1. An apparatus, comprising: a substrate of optical material having a first surface and a second surface; at least one diffractive element disposed on the first or the second surface of said substrate and configured to receive an input optical beam; at least one further diffractive element disposed on the first or the second surface; and at least one optically absorbing area within said substrate, wherein the at least one diffractive element is configured to diffract at least part of the input optical beam to provide at least one diffracted optical beam substantially within the first and the second surfaces, and said at least one further diffractive element is configured to diffract at least part of the at least one diffracted optical beam such that at least part of the at least one diffracted optical beam is coupled out of the substrate, thus said at least one further diffractive element is configured to provide an output optical beam out of said substrate with an expanded exit pupil in one or two dimensions, wherein said input optical beam comprises K wavelength components and said at least one optically absorbing area is configured to absorb M pre-selected components out of the K wavelength components of said at least one diffracted optical beam and to propagate a selected component out of the K wavelength components of said at least one diffracted optical beam, such that the output optical beam comprises said selected component out of the K wavelength components, wherein K is an integer of at least a value of two and M is an integer between 1 and K−1.