Patent ID: 7675673

Claim:
Apparatus comprising: a laser providing an output beam, the output beam including a repeated sequence of at least first and second pulses; an arrangement for directing at least a portion of said output beam sequentially into at least first and second secondary beams, propagating laterally spaced apart from each other, with the first secondary beam including only repeated ones of the first pulses and the second secondary beam including only repeated ones of the second pulses; an arrangement for monitoring the time-averaged power in each of the first and second secondary beams and comparing the monitored time-averaged power with a desired time-averaged power in each of the first and second secondary beams; and an arrangement cooperative with the power monitoring and comparing arrangement for adjusting the duration of the pulses in the first and second secondary beams, such that the monitored time-averaged power in each of the secondary beams is equal to the desired time-averaged power.