Light source system and method

An imaging system comprising a light source system and an imaging arrangement having an entrance pupil, the light source system comprising:

• a multimode laser unit configured to emit a laser beam;
• a first lenslet array positioned in a path of light emitted by the multimode laser unit and configured to form an array of focused spots in a selected plane downstream of said first lenslet array;
• a spatial filter mask carrying an array of pinholes positioned in said selected plane downstream of said first lenslet array;
• a second lenslet array having spatial arrangement of lenslets similar to the first lenslet array and positioned such that said spatial filter mask is in a back focal plane of said second lenslet array, thereby collimating laser light from the array of focused spots into a corresponding array of beamlets;
• and
• a third lenslet array positioned downstream of said second lenslet array, configured for focusing said array of beamlets to form an output spot array at said entrance pupil,
• wherein the imaging system further comprises a beam splitting arrangement positioned downstream of said second lenslet array and configured to split the array of beamlet arrays into at least first and second replications of said array of beamlets, and a delay unit placed in a path of at least one of said first and second replications, wherein the delay unit is configured to delay light passing therethrough by time greater than a temporal coherence time tau of said multimode laser unit, and wherein said third lenslet array is configured for focusing said first and second replications to generate a plurality of mutually incoherent point-like light sources enabling adjustment of at least etendue and exit pupil diameter.

A method comprising:

• providing a light beam comprising a plurality of spatial modes from a multimode laser light source;
• separating said light beam into a plurality of focused spots spatially separated points by a first array of lenses;
• collecting light diverging from said plurality of focused spots by a second array of lenses to provide an array of collimated beamlets;
• splitting said array of collimated beamlets into at least first and second replications of said array of collimated beamlets, and delaying at least one of said first and second replications by a time exceeding a coherence time of the multimode laser;
• and
• focusing said at least first and second replications of beamlets by a third array of lenses onto a selected exit pupil to generate a plurality of mutually incoherent point-like light sources at said exit pupil,
• wherein a number of replications, and focal length of the third array of lenses provides a desired exit pupil diameter and etendue of illumination.