Exploring dipole blockade using high-$n$ strontium Rydberg atoms*

Studies of the production of strongly-polarized quasi-1D high-$n$, $n\sim300$, strontium ``$n$F" Rydberg states in an atomic beam by three-photon excitation in a weak dc field suggest that (in the absence of blockade effects) densities of $\sim10^6 $ $cm^{-3}$ might be achieved. At such densities the interparticle separation, $\sim100$ $\mu m$, becomes comparable to that at which dipole blockade effects are expected to become important. Apparatus modifications are underway to allow the exploration of blockade at very high-$n$ and the effects of the high energy level density. Blockade is also being examined through calculations of the energy spectrum for two interaction atoms. Access to the blockade regime promises creation of Rydberg atoms at well-defined separations whose interactions can be coherently controlled using electric field pulses thereby enabling study of the dynamics of strongly-coupled Rydberg systems.