The Atom-Cavity Microscope
Single Atoms Bound in Orbit by Single Photons

The abstract and full research article can be downloaded from Science via our recent papers page. Also, take a look at the Caltech press release.

Cesium atoms are captured in a MOT (magneto-optical trap) and dropped through a high-finesse optical cavity. A single atom (green arrow) transiting the cavity mode alters the measured transmission of a probe beam (with mean field strength m~1 photon) through the cavity. This allows a real-time inference of the single atom's position.
Between the mirrors the intracavity field forms a standing-wave pattern (along the x-axis) and a Gaussian (in the y-z plane). Individual atom trajectories are channeled by forces from the intracavity field to lie in a y-z plane at a maximum of the standing-wave along x, as indicated by the inset. Even for m~1 photon, these same light forces can trap the atom, causing it to orbit around the center of the cavity mode.

Below are three Quicktime movies of single atom trajectories, reconstructed from experimental data, shown in the plane of the atom-orbit (y-z plane). Below each trajectory is the corresponding transmission of the probe laser through the atom-cavity system, measured at our heterodyne detector. Each second of the movies represents 120 microseconds of real time. More information about reconstructing atom orbits can be found on this page.

Single Atom Orbit #2 Quicktime Movie (3.2MB)

Single Atom Orbit #3 Quicktime Movie (5.8MB)

Movies made with IgorPro .

Click here for a more detailed discussion of trajectory reconstructions, with examples of different cases.

Caltech Quantum Optics Home Page.