Life problems of dc and rf-excited low-power cw CO2 waveguide lasers

Abstract

A number of different, rf‐excited 3‐W cw CO₂ waveguide lasers have been built. Four of these lasers, after continuously working for 15 000–30 000 h, still yield about 70% of their original power output. The design variations cover N₂‐ and CO‐bearing gas mixtures, as well as internal‐ and external‐capacitively coupled excitaton electrodes. A similar laser survived 50 000 5‐min‐ON/5‐min‐OFF cycles without significant mirror damage. We have not been able to find suitable cold cathodes that allow the building of longitudinally dc‐excited cw CO₂ waveguide lasers that work for such extended periods of time.