Lamb Shift of Laser-Dressed Atomic States

We discuss radiative corrections to an atomic two-level system subject to an intense driving laser field. It is shown that the Lamb shift of the laser-dressed states, which are the natural state basis of the combined atom-laser system, cannot be explained in terms of the Lamb shift received by the atomic bare states which is usually observed in spectroscopic experiments. In the final part, we propose an experimental scheme to measure these corrections based on the incoherent resonance fluorescence spectrum of the driven atom.

Figure 1

One of the Mollow sidebands in Eq. (13) without any Lamb shifts (dashed line), corrected by the bare Lamb shift according to Eq. (6) (solid line), and corrected by the fully dressed Lamb shift according to Eq. (12) (dash-dotted line). (b) is a magnification of (a) with $x_1=1008.64\Gamma$, $x_2=1008.67\Gamma$, $y_1=0.05062$, and $y_2=0.05068$, where the vertical lines mark the line centers of the two Lorentzians. The parameters chosen are for the hydrogen $1S$–$2P_{1/2}$ transition with $h=1000$, $\Delta =50\Gamma$, $\Gamma =99.8\mathrm{M}\mathrm{H}\mathrm{z}$, and $L_{\mathrm{b}\mathrm{a}\mathrm{r}\mathrm{e}}=-8185.652\mathrm{M}\mathrm{H}\mathrm{z}$.