Spark Gap Pressure and Lasing Behaviour of a non -Blumlein type Nitrogen Laser

Abstract

The effect of the nitrogen or SF6 pressure in a spark gap of a small rugged free running nitrogen laser (laser gap 2.4 mm, channel length 170 mm) is studied. No significant difference between nitrogen and SF6 as spark gap chamber gases was found. With increase of the spark gap pressure from 1 to 3.5 bar the pulse energy increases from 30 to 70 pJ, at 10 kV, or from 90 to 130 pJ, at 14 kV. The maximum of the laser efficiency is found at lower breakdown voltages with higher spark gap pressures. Pre-ionization by UV light from the spark gap can be excluded, but not that from a corona discharge over the capacitor foil below the laser channel. It is shown that further effort to increase the laser output power must start from the design of a fast spark gap, well integrated into the whole discharge circuit.