arXiv:0903.0524 · Physical Review A
Nonlinear magneto-optical resonances at D1 excitation of R85b and R87b for partially resolved hyperfine F levels
Marcis P. Auzinsh, R. Ferber, F. Gahbauer, Andrey Jarmola, L. Kalvāns
Abstract
Experimental signals of nonlinear magneto-optical resonances at ${D}_{1}$ excitation of natural rubidium in a vapor cell have been obtained and described with experimental accuracy by a detailed theoretical model based on the optical Bloch equations. The ${D}_{1}$ transition of rubidium is a challenging system to analyze theoretically because it contains transitions that are only partially resolved under Doppler broadening. The theoretical model took into account all nearby transitions, the coherence properties of the exciting laser radiation, and the mixing of magnetic sublevels in an external magnetic field and also included averaging over the Doppler profile. The experimental signals were reproduced very well at each hyperfine transition and over a wide range of laser power densities, beam diameters, and laser detunings from the exact transition frequency. The bright resonance expected at the ${F}_{g}=1\ensuremath{\rightarrow}{F}_{e}=2$ transition of $^{87}\text{R}\text{b}$ has been observed. A bright resonance was observed at the ${F}_{g}=2\ensuremath{\rightarrow}{F}_{e}=3$ transition of $^{85}\text{R}\text{b}$, but displaced from the exact position of the transition due to the influence of the nearby ${F}_{g}=2\ensuremath{\rightarrow}{F}_{e}=2$ transition, which is a dark resonance whose contrast is almost 2 orders of magnitude larger than the contrast of the bright resonance at the ${F}_{g}=2\ensuremath{\rightarrow}{F}_{e}=3$ transition. Even in this very delicate situation, the theoretical model described in detail the experimental signals at different laser detunings.