Short active length CuII laser excited by a spherical hollow cathode discharge

Lasing has been reliably obtained at 780.8 nm on the CuII transition in a hollow cathode discharge device with an active length of 54 mm and a cavity length of 400 mm. Five spherical 12 mm diameter cathodes are mounted in series along the laser axis. The spherical cathodes are employed in order to inhibit cathode erosion, improve discharge stability and to extend the useful lifetimes of those metal vapour lasers where the metal is produced by cathode sputtering.