A sealed-off beryllia tube argon ion laser

An argon ion laser is described in which the discharge is confined by a beryllia capillary tube. This has enabled the current density in the discharge to be increased to more than 600 A cm¿2 with negligible gas cleanup. Sealed-off lasers have been life tested for more than 1000 hours without the need for a gas replenishing system and have shown less than 10% change in output. The total output of 1.5 W can be increased to more than 3 W by the application of a magnetic field. This performance is obtained from a 3 mm bore, 30 cm long plasma tube with an argon pressure of 0.7 torr.