Two-dimensional wavelength-beam-combining of lasers using first-order grating stack

A method of two-dimensional wavelength beam combining in a laser system, the method comprising:

• spatially overlapping in a first dimension optical beams from a plurality of laser emitters using a grating stack comprising a plurality of first-order diffraction gratings;
• imaging the optical beams onto the grating stack;
• and
• spatially overlapping in a second dimension the optical beams from the grating stack to generate a multi-wavelength output beam.

A multi-wavelength laser comprising:

• a master oscillator configured to generate a first plurality of optical beams;
• an amplifier array optically coupled to the master oscillator and comprising a plurality of laser elements arranged in a two dimensional array, the amplifier array configured to produce a second plurality of optical beams arranged in a two dimensional array having a first dimension and an orthogonal second dimension;
• a grating stack comprising a plurality of first-order diffraction gratings arranged linearly in the first dimension;
• a dispersive element;
• a cylindrical telescope positioned between the grating stack and the amplifier array and configured to image the second plurality of optical beams from the amplifier array onto the grating stack;
• a first cylindrical transform lens optically coupled to the amplifier array and configured to spatially overlap the second plurality of optical beams in a second dimension creating a first plurality of overlapped optical beams and forming a first region of overlap at the grating stack;
• and
• a second cylindrical transform lens positioned between the dispersive element and the grating stack and configured to receive the first plurality of overlapped optical beams from the grating stack and to spatially overlap the first plurality of overlapped optical beams in the first dimension forming a second region of overlap at the dispersive element;
• wherein the dispersive element transmits a multi-wavelength output beam comprising the spatially overlapped first plurality of overlapped optical beams.