dc-excited and sealed-off operation of the optically pumped 546.1-nm Hg laser

The optically pumped Hg laser at 546.1 nm, first developed by Djeu and Burnham, has now been operated as a sealed-off rather than continuously flowing system, and with dc-excited rather than rf-excited pump lamps in both elliptically focused and close-wrapped configurations. Laser power outputs of ∼1 mW cw have been obtained with ∼100 W excitation into two commercial Hg germicidal lamps, and a power output of ≳3 mW has been obtained from a sealed-off tube with ∼300 W into a single low-pressure ’’Toronto arc’’ pump lamp. Sealed-off operation appears to be stable and long lived, and substantial further performance improvements are expected.