Classification of Light-Induced Desorption of Alkali Atoms in Glass Cells Used in Atomic Physics Experiments

We attempt to provide physical interpretations of light-induced desorption phenomena that have recently been observed for alkali atoms on glass surfaces of alkali vapor cells used in atomic physics experiments. We find that the observed desorption phenomena are closely related to recent studies in surface science, and can probably be understood in the context of these results. If classified in terms of the photon-energy dependence, the coverage and the bonding state of the alkali adsorbates, the phenomena fall into two categories: It appears very likely that the neutralization of isolated ionic adsorbates by photo-excited electron transfer from the substrate is the origin of the desorption induced by ultraviolet light in ultrahigh vacuum cells. The desorption observed in low temperature cells, on the other hand, which is resonantly dependent on photon energy in the visible light range, is quite similar to light-induced desorption stimulated by localized electronic excitation on metallic aggregates. More detailed studies of light-induced desorption events from surfaces well characterized with respect to alkali coverage-dependent ionicity and aggregate morphology appear highly desirable for the development of more efficient alkali atom sources suitable to improve a variety of atomic physics experiments.Comment: 6 pages, 1 figure; minor corrections made, published in e-Journal of Surface Science and Nanotechnology at http://www.jstage.jst.go.jp/article/ejssnt/4/0/4_63/_articl

Atom chip setup for cold Rydberg atom experiments

The design, construction and characterization of an atom chip apparatus for cold Rydberg atom experiments with 87Rb is presented. The apparatus is designed to investigate interactions between Rydberg atoms and the nearby chip surface, as well as the dynamics of Rydberg atoms in a double well. The proposed interrogation scheme is Rydberg electromagnetically induced transparency (Rydberg EIT). Magnetic trapping potentials used to load the chip with atoms are calculated. The atom number and temperature during various phases of the loading sequence are measured using absorption imaging. The room-temperature 4-level ladder-type Rydberg EIT system, in which the 3-level Rydberg EIT system is coupled via microwaves to a second Rydberg state, is investigated experimentally. EIT transmission spectra for different microwave powers and different polarizations of optical fields and microwaves are presented. It is shown that, to explain the observed polarization effects in the probe transmission lineshape, all magnetic sublevels, including the hyperfine structure of both Rydberg levels, have to be taken into account. The corresponding 52-level theory is discussed. Calculations of long-range multipolar Rydberg-atom Rydberg-atom interaction potentials are also presented and discussed