Theoretical seminar | 11 October 2021

Interaction of single atoms and atomic ensembles with twisted light

During the last decade, a significant interest has been paid to the production and application of vortex (or twisted) light beams. These structured beams, that possess a helical phase front and also carry orbital angular momentum (OAM), were found to be a valuable tool for a great variety of studies in atomic, molecular and optical physics. Of particular interest here is interrogation of trapped atoms and ions with vortex light. The use of OAM light allows significant suppression of the AC-Stark shift of transition frequencies if an atom is located near the center of photon beam. Together with the efficient excitation of higher-multipole (dipole-forbidden) channels, this cancellation of the AC-Stark shift makes twisted light promising for studying and employing atomic clock transitions. In this contribution we will discuss recent experimental and theoretical advances in spectroscopy of the dipole-forbidden (atomic clock) transitions with the help of OAM light beams. We will show how the topological charge and polarization of incident twisted light can be used to control these transitions and will discuss the potential of development of ``OAM-based atomic clocks’’. Moreover, in the end of the talk. we will briefly consider interaction of twisted light with cold atomic ensembles.

Main paper/arXiv, related to the seminar, and other references