Multiple preionization discharge TEA CO2 laser

Abstract

A new concept in utilizing preionization in the TEA CO2 laser is presented. The variable adjustment of the delay between the preionization and the main discharge in a pin-grid double discharge TEA CO2 laser permits the use of low He concentrations (?60%), and different CO2/(CO2+N2) ratios (ranging from 1 to 0) at relatively high main discharge storage energy density (150 J/liter). The addition of a different preionization source (Lamberton–Pearson type) to this laser type leads to further increase in overall performance. This permits a completely variable TEA CO2 laser operation over the gas mixture [100–45% He, and CO2/(CO2+N2) ratio from 1 to 0] and the pump energy (to more than 200 J/liter) without the use of any sophisticated discharge circuit configuration or any seeded gas in the laser mixture. We propose a qualitative explanation based on the comprehension of the different electron production–electron loss processes in the laser discharge. This contribution opens up a new point of view in using more profitably the different preionization schemes proposed to date.