Generation of long pulse excimer laser using a novel auto pre-pulse excitation scheme

Abstract

In this paper, we demonstrate a long pulse XeCl excimer laser using a novel, simple and easy to assemble auto pre-pulse excitation circuit. The auto pre-pulse excitation scheme involves a single high voltage switch for driving the UV pre-ionizer, pulser and sustainer which are isolated by saturable inductors made of ferrite cores without any additional circuit. The capacitor banks of exciter circuit are charged by single power supply. The experimental scheme demonstrated here, generates coherent optical laser pulses of duration ~60 ns which is an improvement of about 5 times when the laser is operated with conventional exciter. The laser is capable of generating laser pulses of energy 100 mJ reliably from a discharge volume of 75 cc at a repetition rate of 100 Hz. Long excimer pulses are desired for fiber optic beam delivery of high energy without damaging the core material for various applications. Moreover, long pulse allows large number of laser cavity round trips for the oscillating modes. The micro hole generated by focusing the long pulse XeCl laser beam on metal target shows improved characteristics of the output laser beam.