Rydberg atoms in confined geometries - Experiment and Theory

• Applicants: Dr. Robert Löw; Professor Dr. Stefan Scheel
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 252404023

The control over the internal and external degrees of atoms has reached a level of precision that allows for technical applications superior to solid state devices. The most prominent example is the cesium atom clock, which sets the time reference for the entire planet. In combination with the definition of the speed of light it is also the origin of the meter; thus the measurement of space and time is based on controlling atoms. Atoms can further serve as sensitive probes for magnetic, electric and electromagnetic fields, gravitation, acceleration and rotation. When adding the capability of atomic gases to generate, delay, store and modify light fields, it becomes evident that many more atom-based devices are set to enter our everyday life. A landmark is set by the chip scale atomic clock (CSAC) by Symmetricom, in which all components have been miniaturized to make it integrable and compatible with current technologies present in industry. However, miniaturization can sometimes also be a burden, given that much closer confining walls are more likely to interact with the atoms in an unwanted way.The scientific questions to be answered in this proposal are on the one hand how to minimise the coupling of atoms to a nearby surface, and on the other hand the active use of the surface to mediate interactions between (Rydberg) atoms. The main topic to be addressed here are the interactions of cesium atoms with dielectric materials. The level of optical excitation of the atoms will cover low-lying states as well as highly excited Rydberg states. The experiments will work with thermal atoms at room temperature. Our choice of dielectric materials is mainly driven by device applications. We are mostly interested in quartz glass, which is the standard material for vapour cells. An especially important material for our investigations is diamond, as the absence of optical excitations in the infrared and far-infrared meets the needs of Rydberg atoms, which exhibit strong dipole transitions in this range of wavelengths.In a further processing step we can alter the spectra of excitations in the solid by tailoring material properties such as material thickness, arrangement of layers etc. to either suppress or enhance the atom-wall coupling. The latter might be beneficial for all effects relying on optical saturation by increasing the light scattering rate where the absence or at least the accurate knowledge of the coupling is desirable for most sensing applications.The proposal brings together two groups at the Universities of Stuttgart and Rostock with world-leading expertise in experimental Rydberg physics (Stuttgart) and theoretical atom-surface physics (Rostock). The combined effort promises to yield new insights into coherent manipulation of atoms in confined geometries.

• DFG Programme: Research Grants