Nuclear-pumped near-infrared quasi-cw laser based on transitions in the nitrogen and carbon atoms

Abstract

Lasing on transitions in the nitrogen (λ = 859.4, 862.9, 904.6, and 938.7 nm) and carbon (λ = 833.5 and 940.6 nm) atoms was excited in high-pressure gas mixtures by uranium fission fragments. Stimulated emission of the λ = 859.4, 904.6, and 938.7 nm lines was observed for the first time under nuclear pumping conditions. The gas composition was optimised on the basis of the lasing characteristics of mixtures of Ne with N2, CO, and CO2. A study was also made of the influence of Ar, Kr, and He additives on the laser parameters. The maximum output power of 120 W (at an efficiency of ~ 0.3%) was obtained for the λ = 940.6 nm line emitted by a mixture of the Ne : Ar : CO = 36000 : 1000 : 1 mixture at a pressure of 75 kPa. The lowest lasing thresholds of ~ 2 W cm-3 were observed for the λ = 859.4 and 862.9 nm lines emitted by an Ne—N2 mixture.