Formation of Pulsed Volume Discharges using Hollow Plasma-Cathode

New control method of a pulsed volume discharge in CO2 laser gas of 13.3 kPa pressure is studied using a pair of hollow electrodes that acts as a plasma cathode.The pulsed operation of the hollow cathode plasma of 0.75 mm2 ×0.7 mm in volume initiates a stable volume discharge of 0.75 mm2 ×100 mm in volume.The hollow plasma-cathode improves the stability of volume discharge, so that the repetitive and long pulsed operation is possible up to 1 kHz and 100 µsec, respectively.The current owing path through the hollow and the volume discharge changes according to the current values of the both discharges.The measured small signal gain with 10 cm discharge shows the apparent ampli cation of a CO2 laser beam.