Progress Toward a Flexible Ultraviolet Waveguide Laser: Intense Rare-Gas Discharges in 320- $\mu\hbox {m}$ -Diameter Capillary

Uniform and intense pulsed discharges have been generated in a 320-μm-inner-diameter capillary, which is 30 cm in length, and backfilled with 100-500 torr of Ne, Ar, or Xe. Current and atomic emission rise times <; 400 ns have been achieved with instantaneous power loadings of the plasma exceeding 1MW · cm^-3. Spectra recorded in the ultraviolet over a range of gas pressures and energy stored in the driver circuit suggest that gain is produced in 500-torr Ne for the 247.3-nm line of Ne²⁺. Similar behavior is observed for the 251.7- and 288.4-nm transitions of Ar⁺ and Ar²⁺, respectively.