Auto-prepulse operation of a long-pulse XeCl laser

A standard corona preionized XeC1 laser prototype has been excited by a very simple L-C circuit consisting of a large storage capacitance charged at relatively low voltage (12 kV) and discharged via a switch on the electrodes, tightly coupled with the peaking capacitors. The resulting overvoltage following the switch closure behaves as an effective and automatic prepulse, providing a homogeneous discharge lasting up to 400 ns. Energy output levels of the order of 150 mJ at 1.4% overall efficiency have been achieved.