A beam-forming optical system comprising: an illumination unit comprising a plurality of light sources configured to emit a plurality of beams , the plurality of light sources comprising at least four laser diodes; an optical arrangement of lenses configured to transmit all of the plurality of beams onto a acoustic optical modulator AOM , wherein the AOM comprises a single crystal which modulates all of the plurality of incident beams; wherein the optical arrangement comprises: a cylindrical lens , positioned to receive all of the plurality of beams incident on the cylindrical lens at different angles, and configured to collimate the plurality of beams along a first direction which is parallel to an acoustic direction of the AOM ; and a lens system , positioned to receive all of the plurality of beams transmitted by the cylindrical lens ; the AOM comprising an aperture , wherein the AOM is positioned to receive all of the plurality of beams transmitted by the lens system into the aperture such that the individual beams overlap in one position in the AOM , wherein each of the beams impinge the AOM at different angles; and the AOM comprising a set of channels, each channel configured to modulate a portion of all of the plurality of beams incident thereon, and to consecutively diffract the portion of the plurality of beams associated with that channel as an acoustic wave propagates along the channel in an acoustic direction and a portion of an image of an AOM window is moved across an exposure plane over time, so that all beams are exposed on a same spot on the exposure plane . an illumination unit comprising a plurality of light sources configured to emit a plurality of beams , the plurality of light sources comprising at least four laser diodes; an optical arrangement of lenses configured to transmit all of the plurality of beams onto a acoustic optical modulator AOM , wherein the AOM comprises a single crystal which modulates all of the plurality of incident beams; wherein the optical arrangement comprises: a cylindrical lens , positioned to receive all of the plurality of beams incident on the cylindrical lens at different angles, and configured to collimate the plurality of beams along a first direction which is parallel to an acoustic direction of the AOM ; and a lens system , positioned to receive all of the plurality of beams transmitted by the cylindrical lens ; a cylindrical lens , positioned to receive all of the plurality of beams incident on the cylindrical lens at different angles, and configured to collimate the plurality of beams along a first direction which is parallel to an acoustic direction of the AOM ; and a lens system , positioned to receive all of the plurality of beams transmitted by the cylindrical lens ; the AOM comprising an aperture , wherein the AOM is positioned to receive all of the plurality of beams transmitted by the lens system into the aperture such that the individual beams overlap in one position in the AOM , wherein each of the beams impinge the AOM at different angles; and the AOM comprising a set of channels, each channel configured to modulate a portion of all of the plurality of beams incident thereon, and to consecutively diffract the portion of the plurality of beams associated with that channel as an acoustic wave propagates along the channel in an acoustic direction and a portion of an image of an AOM window is moved across an exposure plane over time, so that all beams are exposed on a same spot on the exposure plane . <EOS>