An Atom is Trapped by the Field of Just One Photon
DOI: 10.1063/1.1292469
Researchers have been pushing atoms around with laser beams for many years, cooling them to record low temperatures and capturing them in confined spaces. Most such efforts require many photons. The field of a single photon is not generally strong enough to corral an atom—unless, that is, the light field is enhanced by confinement within a tiny cavity and the atom enters at a crawl. Then the coupling energy of the atom to the field can exceed the atom’s kinetic energy, and the atom can become ensnared. A group from Caltech and the University of Auckland, and also a group at the Max Planck Institute for Quantum Optics in Garching, Germany, recently created the required conditions by combining cavity quantum electrodynamics with laser trapping and cooling; both groups succeeded in confining single atoms within optical cavities with an average of one photon in the cavity.
