On the excitation mechanism of the oxygen laser in a fast plasma mixing device

A flowing hollow cathode rare gas plasma crossed with an oxygen (O ₂) beam was used to operate an atomic oxygen laser at 8446.7 Å. Laser action based on energy transfer collisions was accomplished only with pure helium plasmas. With additions of 0.2% neon or 0.1% argon to the helium plasma, the laser ceased to operate and fluorescence was reduced. No fluorescence was observed if other O donors such as CO, CO₂, or N₂O were used. The excitation mechanisms for different O donor and rare gas combinations and different excitation methods are discussed