Patent ID: 7864423

Claim:
An apparatus for spectrally filtering at least one input beam, comprising: a spectrally dispersive element configured to disperse spectral components of at least one input beam at respective angles in a spectral plane; one or more optical elements configured to change at least some of the angles of the propagation axes of the dispersed spectral components; and a reflective surface configured to receive a plurality of the dispersed spectral components, and to tilt to select at least one and fewer than all of the received spectral components to be directed to an output spatial mode; wherein the one or more optical elements are configured such that the transverse spatial extent of the input beam on the spectrally dispersive element is larger than the transverse spatial extent of the plurality of dispersed spectral components incident on the reflective surface, and the one or more optical elements are further configured to limit the total angular dispersion of the dispersed spectral components to be less than a tilt range of the reflective surface.