Patent ID: 9310535
Filing Date: 2016-04-12
CPC Classification: G02B

Claim Text:
1. An optical diffraction grating comprising: a grating substrate having substantially flat first and second surfaces, which substrate is substantially transparent over an operational wavelength range that includes a design wavelength λ, has a temperature-dependent refractive index n a set of grating lines formed in or on the substrate that are substantially parallel to the first substrate surface and characterized by a grating spacing Λ, wherein: the first and second substrate surfaces are non-parallel and form a dihedral angle α; the gratings lines are substantially perpendicular to a plane of incidence defined by surface-normal vectors of the first and second substrate surfaces; the optical diffraction grating is arranged as a reflection grating arranged to diffract, at a diffraction anile θ variation of the diffraction angle θ