Spectral-based correction of laser bar smile

A laser light source comprising:

• a semiconductor laser array comprising a plurality of semiconductor lasers arranged along a first direction, at least some of said semiconductor lasers also having different positions along a second direction orthogonal to said first direction, said plurality of semiconductor lasers including first and second semiconductor lasers having different positions both along said first and second directions, said first and second semiconductor lasers outputting diverging beams of laser light having a bandwidth that includes a plurality of wavelengths;
• a collimation region disposed to receive said laser light from said first and second semiconductor lasers and configured to transmit laser light from said first and second semiconductor lasers that is more collimated;
• a dispersion region having angular dispersion disposed to receive light from said first and second lasers that is transmitted through said collimation region, said dispersion region configured to distribute different wavelengths of said plurality of wavelengths in different directions;
• and
• a reflective surface that is partially reflective and partially transmissive positioned to receive said different wavelengths from said dispersion region and reflect a portion of said light back to said dispersion region,
• wherein at least a portion of light from said first semiconductor laser having a first wavelength is incident on said dispersion region and transmitted through or reflected from said dispersion region so as to be normal to said reflective surface such that at least some of said light is retroreflected back to said dispersion region, onto said collimation region and to said first semiconductor laser, and
• wherein at least a portion of light from said second semiconductor laser having a second wavelength different than the first wavelength is incident on said dispersion region at an angle and transmitted through or reflected form said dispersion region and re-directed so as to be normal to said reflective surface such that at least some of said light is retroreflected back to said dispersion region, onto said collimation region and to said second semiconductor laser, and
• wherein at least a portion of said light from said first and second semiconductor lasers is transmitted through said reflective surface at normal incidence to said reflective surface such that light from said first and second lasers transmitted through said reflective surface is more parallel to each other than light from said first and second lasers incident on said dispersion region and is thus light from said semiconductor array is more collimated upon output from said laser light source.