Nano-Photonic Quantum Interfaces for Cold Neutral Atoms
Prof. Arno Rauschenbeutel (Institute of Atomic and Subatomic Physics, Vienna)

I will describe recent experimental work on the quantum mechanical coupling of light and matter using the evanescent field surrounding specially designed optical fibers. In a first experiment, we trap and optically interface laser-cooled cesium atoms in a two-color evanescent field around a silica nanofiber. The atoms are localized in a one-dimensional optical lattice 200 nm above the nanofiber surface and can be efficiently interrogated with light which is sent through the nanofiber. In a second experiment, single atoms are strongly coupled to a whispering-gallery-mode microresonator. There, the light exhibits a strong longitudinal polarization component which fundamentally alters the interaction with matter. Taking advantage of this effect, we recently demonstrated highly efficient switching of signals between two optical fibers controlled by a single atom. If time permits, I will discuss possible applications of our nanofiber-based quantum interfaces as practical building blocks in an optical fiber quantum network.