Pulsed Helium-Neon Gas Laser Applications

Abstract

The pulsed helium-neon gas laser has provided pulse power more than three orders of magnitude above the average power afforded by CW operation. Analyses of the power-limiting factors show that still greater increases may be expected. By increasing the size of the laser tube several times, by optimizing the gas ratio and pressure, by optimizing reflectivity and transmissivity of the reflecting mirrors, and by controlling the shape and application of the exciting voltage pulse, peak power outputs in the kilowatt range are theoretically possible. A power of 100 watts has been achieved in the laboratory at pulse rates up to 250 cps. Such a result brings the gas laser out of the low power category and into the intermediate power range. The results of range calculations show that 100 w pulse power will provide a radar range of approximately 10 km against a target having a diffuse reflectivity of 0.1, and a range of over 100 km with a cooperative target. Against a bright cloud background only the cooperative target can be used. The range will then be reduced to approximately 20 km. An automatic tracking radar system has been synthesized utilizing the pulsed gas laser as a transmitting component. A brief parametric analysis has beem made and some of the advantages of the optical radar over its microwave counterpart have been outlined.