Abstract

In recent years UV excimer discharge lasers find wide use in microelectronics, photolithography, and medicine. In medical applications of special interest is the use of these lasers in ophthalmology for reprofiling the external surface of the cornea and healing of eye diseases. The excimer lasers with radiation energy of some joules and pulse frequency of hundreds of hertzs and higher are required for industrial applications. To achieve such radiation parameters, it is necessary to use cooling systems in laser exciting circuits, to use thyratrons as commutators providing their normal mode of operation, and to use saturable reactors and magnetic switch control in the exciting circuits. Unlike industrial lasers, particularly the lasers for ophthalmology, a pulse frequency is limited by 10-20 Hz to avoid thermal damages of operated tissue. In this case the devices are cycled, it is connected with the replacement of patients, and radiation energy is limited by some hundreds of millijoules. The minimum pulse duration and high homogeneity of beam of light are desirable. To attain such parameters of laser radiation it is possible to simplify the laser exciting circuit sufficiently by eliminating not only the cooling system, but also saturable reactors or magnetic switch control by substituting the thyratron on the spark gap that has a sufficiently lower inductance. However, it is necessary to analyze carefully and to optimize the exciting circuit for providing not only the high efficiency of laser (and hence its resource), but the required energy of generation with a high homogeneity of beam.

© 1994 IEEE