Oscillation and gain characteristics of high power co-axially excited N 2 gas lasers

Abstract

A new type of co-axial discharge gas laser has been developed as a nitrogen laser, and the gain properties have been measured. The co-axial discharge tube consists of a ceramic pipe of inner diameter of 5 mm and length of 15 cm with two metallic electrodes at both ends. The excitation discharge was activated using a capacitor transfer circuit with a special pre-ionization discharge through the ceramic pipe. When the tube is used as an oscillator, an output laser energy of 0.45 mJ was obtained with pure N 2 gas at pressure of 933 Pa (7 Torr). The time resolved gain measurement of N 2 laser was made in the oscillator–amplifier configuration, and the value of the peak gain coefficient was estimated to 0.1 cm −1. The circuit analysis of the discharge circuit was also made to estimate discharge resistances, inductances and currents in the excitation circuit. The laser output increased up to 1.95 mJ at the charging voltage of 28 kV when the length and inner diameter of the discharge tube were increased to 30 cm and 9 mm respectively.