Reduction in the line width of an injection laser by resonant Rayleigh scattering in a fiber ring interferometer

An investigation was made of the radiation emitted by argon mixed with nitrogen and excited by a high-power proton beam. The results indicated that amplification in this mixture was possible as a result of np' –4 s and np –4 s' ( n = 5–7) transitions because of clearing of the 4 s levels by resonant transfer of the excitation energy to a nitrogen molecule. Lasing was observed as a result of a transition in Ar I at λ = 344.3 nm.