Energy-Transfer Kinetics for Xe (6p[1/2]₀) Atoms in Kr, Ar, Ne, and He

The kinetic processes for the Xe (6p[1/2]₀) atoms in Kr, Ar, Ne, and He buffer gases were studied. We found that Kr, Ar, and Ne atoms can be used to switch the amplified spontaneous emission (ASE) channel from 3408 nm (6p[1/2]₀-6s'[1/2]₁) to 3680 nm (5d[1/2]₁-6p[1/2]₁), while Xe and He atoms do not show such a phenomenon. This ASE channel switch is mainly ascribed to the fast transfer of 6p[1/2]₀ → 5d[1/2]₁. On the basis of the rate equations for two-state coupling (energy-transfer processes between the two states are very rapid), the reason why the ASE channel switch effect normally coincides with a double exponential decay of the spontaneous emission at 828 nm (6p[1/2]₀-6s[3/2]₁) is explained. The actual situations in Xe, Ar, Ne, and He follow this rule. However, the strictly single exponential decay of the spontaneous emission at 828 nm and strong ASE channel switch effect simultaneously emerge in Kr. This indicates that the transfer of 6p[1/2]₀ → 5d[1/2]₁ in Kr does not occur via two-state coupling, but via two steps of near-resonance collision through the 5s[3/2]₂ (Kr) state as the intermediate state (6p[1/2]₀ → 5s[3/2]₂ (Kr) → 5d[1/2]₁). In addition, we found Xe (6p[1/2]₀) atoms strongly tend to reach the 6p[3/2]₂, 6p[3/2]₁, and 6p[5/2]₂ states through the 5s[3/2]₂ (Kr) state as the intermediate state in Kr. The 5s[3/2]₂ (Kr) state plays a very important role in the energy-transfer kinetics for the Xe (6p[1/2]₀) atoms. Kr is probably an excellent buffer gas for laser systems based on Xe.