Relative transition probabilities in deexcitation of atomic states by collisional quenching: Cs6P122→6S122

Abstract

Nuclear-spin-independent relative probabilities for quenching-induced transitions between the Zeeman sublevels of the $6{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ and $6{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}$ states of Cs have been measured in a new application of optical pumping. The results for Cs-${\mathrm{N}}_2$ collisions at 15 °C are $K_1({}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}\to {}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}, \Delta m_J=0)=0.5\mathrm{}\pm 0.06$, and $K_2({}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}\to {}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}, \Delta m_J=\pm 1)=0.44\pm 0.06$. The theoretical analysis includes a full treatment of the effect of the hyperfine interaction on relative quenching probabilities, yielding probabilities for $|F^{\prime }, m_{F^{\prime }}〉\to |F, m_F〉$ transitions parametrized in terms of $K_1$ and $K_2$. Full solutions to the pumping equations require knowledge of individual populations of excited-state sublevels: Appropriate analytic solutions for these populations have been calculated in the weak-pumping limit. The experimental results indicate that quenching collisions modify atomic de-excitation probabilities in ways which enhance the efficiency of optical pumping.