Efficient three-photon excitation of quasi-1D $n\sim300$ strontium Rydberg atoms

The production of high $n$, $n\sim300$, quasi-one-dimensional (quasi-1D) strontium Rydberg atoms via three-photon excitation of extreme Stark states in the presence of a weak dc field is explored. The experimental data are analyzed with the aid of classical trajectory Monte Carlo simulations and quantum calculations using a two-active-electron model. The results demonstrate that strongly-polarized quasi-1D states can be generated with much higher production rates than achieved using two-photon excitation. Furthermore, the data suggest that densities approaching those at which blockade effects become important might be realized opening up the opportunity to examine the behavior of strongly-coupled Rydberg atom pairs.