Atom trapping and cooling inside a high Finesse optical resonator

We investigate a single atom strongly coupled to a cavity mode and develop new techniques for storing, observing and cooling the atom. To minimize the light shift of all atomic energy levels we trapped the atom in the dark center of a three-dimensional confinement consisting of blue-detuned cavity modes of different longitudinal and transverse order. We utilized dispersive measurements to detect a single atom. We pushed the detection scheme, based on the detection of single photons from a probe beam transmitted through the cavity, to estimate the position of the atom in the trap in real-time. We used this information to apply real-time feedback control of the motion of the atom to finally realize real-time, feedback cooling.

Selected references:
A. Kubanek, et al., 
Feedback control of a single atom in an optical cavity“. Applied Physics B 102, 433–442 (2011)

M. Koch, et al., Feedback Cooling of a Single Neutral Atom“. Physical Review Letters 105, 173003 (2010)

A. Kubanek, et al., Photon-by-photon feedback control of a single-atom trajectory“. Nature 462, 898–901 (2009)

T. Puppe, et al., Trapping and Observing Single Atoms in a Blue-Detuned Intracavity Dipole Trap“. Physical Review Letters 99, 013002 (2007)