High-gain hollow-cathode metal ion lasers for the UV and VUV

Previous studies have shown that a metal ion laser pumped by a segmented hollow-cathode (SHC) discharge gives a performance superior to that obtained from a conventional low-voltage hollow-cathode (CHC) device. This results from the increased voltage and much higher slope of the voltage-current characteristic for the SHC compared with that for the HC, whilst still allowing the oscillation of focussed beam electrons. Due to the increased gain we could study the AuII and the CuII UV laser transitions for operation with external mirrors. This allowed the measurement of the small-signal gain by inserting a variable calibrated loss into the optical cavity.