Series of stacked confocal pulse stretchers for speckle reduction

A pulse stretcher system configured to stretch pulses of light output by a laser chamber, the pulse stretcher system comprising:

• a vertically positioned optical pulse stretcher, wherein the vertically positioned optical pulse stretcher extends along a first longitudinal axis oriented perpendicular or approximately perpendicular to a propagation direction of the pulses of light where the pulses of light emerge from the laser chamber;
• and
• a horizontally positioned optical pulse stretcher optically coupled to the vertically positioned optical pulse stretcher, wherein the horizontally positioned optical pulse stretcher extends along a second longitudinal axis that is perpendicular or approximately perpendicular to the first longitudinal axis;
• wherein the horizontally positioned optical pulse stretcher has a longer delay path length than the vertically positioned optical pulse stretcher;
• wherein the horizontally positioned optical pulse stretcher comprises a nitrogen purged environment;
• wherein a combination of the horizontally positioned optical pulse stretcher and the vertically positioned optical pulse stretcher comprises four pulse stretcher stages;
• wherein the horizontally positioned optical pulse stretcher comprises a plurality of pulse stretcher stages among the four pulsed stretcher stages;
• wherein a first pulse stretcher stage among the plurality of pulse stretcher stages comprises:
• a first plurality of mirrors, and
• a first beam splitter configured to receive a pulsed laser beam and to direct a portion of the pulsed laser beam into a first optical circuit formed by the first beam splitter and the first plurality of mirrors, and
• wherein a second pulse stretcher stage among the plurality of pulse stretcher stages comprises:
• a second plurality of mirrors, and
• a second beam splitter configured to receive a partially stretched pulsed laser beam from the first pulse stretcher stage and to direct a portion of the partially stretched pulsed laser beam into a second optical circuit formed by the second beam splitter and the second plurality of mirrors.