Master Thesis Defence by Jacob Thornfeldt Hansen

Motional quantum states of cesium atoms trapped around a nanofiber

The interaction of mesoscopic atomic ensembles with a single optical mode in the strong coupling regime can be realized using optical nanofibers. The evanescent field of light, guided by an optical fiber of sub-wavelength diameter, allows for strong confinement of neutral atoms by utilizing dipole forces. The same strong confinement allows for the resolution of motional sidebands, which reveal information about the motional state of the atomic ensemble. In this thesis, the fabrication, characterization and installation of a new nanofiber is presented. The analysis of sideband resolved Raman spectra gives us an insight into the temperature of trapped Cesium atoms. Different methods of accounting for systematic errors are presented and critically evaluated. The motional states of the trap potential are studied numerically and comparisons with the experimental temperature estimation method show good agreement with the numerical results.

Supervisors: Jörg Helge Müller, Eugene Polzik
Censor: Alexander Huck