Laser action in Al II and He I in a slot cathode discharge

Laser excitation of metal vapors and gases in four types of hollow cathodes employing transverse electrical discharges is discussed. A water-cooled slot cathode is demonstrated to provide two distinct laser excitation modes. cw laser action at 7471, 7042, and 6920 Å from Al II, which is cathodically sputtered by Ne/H2 mixtures and excited in charge-transfer collisions, is reported. Pulsed laser action at 7065.21 and 7065.17 Å from He I, which is excited in direct electron impact collisions in the presence of H2 is reported. Laser performance data relating to gas pressures, currents, pulse widths, and gains are presented. The importance of H2 admixtures to the laser species is discussed.