Patent ID: 7088758

Claim:
A narrow band short pulse duration gas discharge laser output light pulse beam producing system, producing a beam comprising laser output light pulses at a selected pulse repetition rate, comprising: a dispersive center wavelength selection optic selecting at least one center wavelength for each pulse determined at least in part by the angle of incidence of the laser light pulse beam containing the respective pulse on the dispersive wavelength selection optic: a tuning mechanism operative to select at least one angle of incidence of a first spatially defined portion of the laser light pulse beam containing the respective pulse upon the dispersive center wavelength selection optic: and, the tuning mechanism comprising a variably refractive optical element defining a plurality of refractive angular displacements of the first spatially defined portion of the laser light pulse beam passing through the variably refractive optical element at one of a plurality of positions of incidence of the laser light pulse beam on the variably refractive optical element; the laser output light pulse beam comprising a plurality pulses having a first center wavelength and a plurality of pulses having a second center wavelength separated by a selected difference in the respective center wavelengths; a laser output light pulse beam parameter metrology nodule; a laser controller; a wavelength controller controlling the respective center wavelengths and the difference in center wavelengths in response to at least one signal from the beam parameter metrology module and at least one signal from the laser controller.