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PULSED LASER SYSTEM HAVING IMPROVED ENERGY CONTROL WITH IMPROVED POWER SUPPLY LASER EMISSION ENERGY SENSOR AND ADJUSTABLE REPETITION RATE CONTROL FEATURES

  • US 3,806,829 A
  • Filed: 04/13/1971
  • Issued: 04/23/1974
  • Est. Priority Date: 04/13/1971
  • Status: Expired due to Term
First Claim
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1. A pulsed laser system and control including in combination pumped laser means for producing a relatively high intensity laser beam of coherent light of high average energy which is variable over a predetermined range, pumping and resonator means coupled to the laser means for inducing emission of the laser beam at an energy level proportional to the energy level of the output emission from the pumping and resonator means, variable charge capacitor storage circuit means coupled to and supplying Electric energy to said pumping and resonator means at a charge elvel that determines the energy level of the stimulated output laser beam, electric power supply means energized from a conventional source of an electric power and coupled to and supplying electric energy to said variable charge capacitor storage circuit means, charging level control circuit means coupled to said electric power supply means for controlling the energy level to which the variable charge capacitor storage circuit means is charged, said electric power supply means comprising a voltage step-up transformer and high voltage rectifier circuit means, a low voltage monocyclic constant current charging networks for supplying said variable charge capacitor storage circuit means through said voltage step-up transformer and high voltage rectifier circuit means, said charging level control circuit means comprising fast responding SCR crowbar short circuiting means coupled across the output from said low voltage monocyclic constant current charging network for short circuiting the output from the network to thereby discontinue in a fast responding manner the charging of the variable charge capacitor storage circuit means from the monocyclic constant current charging network, capacitor storage circuit energy level sensing means coupled to the variable charge capacitor storage circuit means for sensing the energy level to which the variable charge capacitor storage circuit means is charged, computation circuit means coupled to the energy level sensing means for converting the sensed measure of energy into an electric signal representative of the total actual energy stored in the variable charge capacitor storage circuit means measured in terms of joules of energy, feedback control circuit means for controlling the operation of said SCR crowbar short circuiting means and responsive to the output from said computation circuit means for automatically discontinuing charging of said variable charge capacitor storage circuit means at a desired storage energy level, means disposed in the optical path of the laser beam for partially diverting a fractional portion of the beam, photosensitive means responsive to the diverted fractional portion of the laser beam for deriving sensed actual laser beam energy feedback signal, and comparison circuit means responsive to the output from said photosensitive means and to a preprogrammed value of energy level for controlling the operation of the computation circuit means for appropriately compensating the stored energy level in the variable charge capacitor storage circuit means intermediate each pulse operation of the laser system in accordance with the value of the sensed actual laser beam energy feedback signal whereby losses incurred in the high power pulsed laser system are compensated by adjusting the stored energy level of the capacitor storage circuit means to a value sufficient to make up for such losses following each pulsed operation of the laser system.

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