Laser Manipulation of Atoms

Photons from a near-resonant laser will be absorbed and re-emitted by an atom. Each event gives a recoil in the amount of the photon's momentum. Since the emission pattern is symmetric, the emitted photons contribute no net momentum change. The atoms will feel a net force from the laser ("light pressure").

The single-photon recoil for Cs is 3.5 mm per second. But since it can scatter more than 10,000,000 photons per second, the atoms can feel an acceleration as large as 50,000 meters/second or about 5000 g's.

A University of Colorado Interactive Java Applet that demonstrates optical molasses.