Photoionization of Rydberg Atoms in Optical Lattices

Abstract

We develop a formalism for photoionization (PI) and potential energy curves (PECs) of Rydberg atoms in ponderomotive optical lattices and apply it to examples covering several regimes of the optical-lattice depth. The effect of lattice-induced PI on Rydberg-atom lifetime ranges from noticeable to highly dominant when compared with natural decay. The PI behavior is governed by the generally rapid decrease of the PI cross sections as a function of angular-momentum ( ), and by lattice-induced -mixing across the optical-lattice PECs. In GHz-deep lattices, -mixing leads to a rich PEC structure, and the significant low-PI cross sections are distributed over many latticemixed Rydberg states. In lattices less than several tens-of-MHz deep, atoms on low-PECs are essentially -mixing-free and maintain large PI cross sections, while atoms on high-PECs trend towards being PI-free. Characterization of PI in GHz-deep Rydberg-atom lattices may be beneficial for optical control and quantum-state manipulation of Rydberg atoms, while data on PI in shallower lattices are potentially useful in high-precision spectroscopy and quantum-computing applications of lattice-confined Rydberg atoms.

Long-Range Atom–Ion Rydberg Molecule: A Novel Molecular Binding Mechanism

“…As an example, we consider the wavelength of λ PI = 1064 nm for which high power laser sources are available. According to [34], the photoionization cross section σ PI for direct photoionization starting from Rb Rydberg P states ranges from about 1 × 10 −21 cm 2 for n = 90 to about 2 × 10 −19 cm 2 for n = 20. Consequently, when addressing, e.g., the 17P state of Rb, a laser intensity on the order of 10 5 W cm −2 is needed to obtain a photoionization rate comparable to the rate for natural radiative decay.…”