Ponderomotive Optical Lattice Trap for Rydberg Atoms
Georg Raithel lab, University of Michigan
Participating Students: Sarah Anderson, Yun-Jhih Chen, Kaitlin Moore
(Illustration credit: Kelly Younge)
June 21, 2012 -- We have recently investigated the angular dependence of the optical lattice's Rydberg trapping potentials. While the angular dependence of optical lattice potentials for ground-state atoms is well known and widely utilized, our work provides the first experimental investigation of such dependence for Rydberg atoms. An understanding of this dependence is important for the trap to be employed in applications. For example, angular degrees of freedom could be used to tune the Rydberg trapping potentials as desired for specific applications.
The potentials experienced by Rydberg atoms in the optical lattice depends on how the Rydberg wavefunctions overlap with the lattice wells. The angular dependence of the potentials therefore arises from the shape of the Rydberg wavefunction and its orientation relative to the lattice axis. A Rydberg state whose wavefunction is elongated in the direction transverse to the lattice axis (B) will experience more deeply modulated lattice potentials than states elongated in the direction of the lattice axis (A).
The detailed work demonstrating the angular dependence of the lattice's potentials for Rydberg atoms can be found at Phys. Rev. Lett. 109, 023001 (2012) or under the "Resources" tab.
Dec 21, 2011 -- We have demonstrated that a 1064 nm optical lattice traps Rb Rydberg atoms with 90% efficiency. We also investigated photoionization of the Rydberg atoms in the lattice and measured dwell times of the Rydberg atoms in the lattice. Detailed work can be found at Phys. Rev. Lett. 107, 263001 (2011). A brief news report describing these results has also been published by the University of Michigan News Service.
Figure: Rydberg atoms are prepared at maxima of the Rydberg trapping potential in the 1064 nm optical lattice, where the majority of atoms are un-trapped (A). To address this difficulty, we implemented an electro-optic method to flip the lattice immediately after Rydberg excitation. The lattice flip results in Rydberg atoms located at minima in the Rydberg-trapping potential, where they are trapped (B). We demonstrated that this method results in a 90% Rydberg-atom trapping efficiency.