Patent ID: 8441729

Claim:
An optical arrangement, comprising: a diffraction grating comprising a plurality of diffraction structures following one another periodically at a spacing of a grating period (d); and a base having a base surface supporting the plurality of diffraction structures, wherein each of the plurality of diffraction structures comprises: a blaze flank; and an antiblaze flank, the blaze flanks being arranged at an angle (β) relative to the base surface, the antiblaze flanks being arranged at an angle (α) relative to the base surface, and neighbouring blaze and antiblaze flanks enclosing an apex angle (γ), and wherein, during use: the optical arrangement is configured so that an incident light beam at a wavelength (λ) is arranged at a Littrow angle (θ L ) relative to a grating normal of the diffraction grating; the angle (β) is greater than the Littrow angle (θ L ) by at least 4°; for at least one polarization direction, a diffraction efficiency is at least approximately maximal in a diffraction order m, which fulfils the condition (2((m+1)/m)−1)sin θ L ≧1; and the diffraction order m is a largest possible last propagating diffraction order or the diffraction order m deviates from the largest possible last propagating diffraction order by a number which lies in a range from 1 to 20.