Two-photon excitation of the 5 (2)D states of rubidium.

Abstract

We calculate the excitation rates of the 5 $^{2}$${\mathit{D}}_{3/2}$ and 5 $^{2}$${\mathit{D}}_{5/2}$ states of rubidium through the simultaneous absorption of two photons of different frequencies by the ground 5 $^{2}$${\mathit{S}}_{1/2}$ state. We include spin-orbit effects in the contribution of the 5P and 6P states, situated between the initial and final states, which give rise to the resonance structure in the two-photon spectrum. We indicate how our results can be used for the case in which the transition takes place between states with specified total angular momenta F, for both $^{85}\mathrm{Rb}$ and $^{87}\mathrm{Rb}$. For the case of counterpropagating photons with the same frequency, our results are compared with existing experimental data.