Editor's Summary

29 October 2009

Show of strength: neutral atoms feel the ponderomotive force

A Nature paper of 1957 (http://go.nature.com/LDtDIb) described a force on charged particles in an inhomogeneous electric field originating from the equations for the electromagnetic Lorentz force. It was soon realized that this 'ponderomotive force' could be used to trap and control electrons. But the force is weak and it was not until the advent of modern lasers that it has been exploited, in particle accelerators and inertial confinement fusion devices. Now a new incarnation of the force has been identified. Ulrich Eichmann et al. observed previously unconsidered strong kinematic forces on neutral atoms in short-pulse laser fields. The ponderomotive force on electrons is the driving mechanism, producing ultra-strong acceleration of neutral atoms greater that Earth's gravitational acceleration by 14 orders of magnitude. A force of such strength may lead to new applications in both fundamental and applied physics. On the cover, a record of the deflection of neutral helium atoms after interaction with a focused laser beam.

AuthorsMaking the paper: Ulli Eichmann

Physicists push excited neutral atoms to ultrafast speeds.


LetterAcceleration of neutral atoms in strong short-pulse laser fields

U. Eichmann, T. Nubbemeyer, H. Rottke & W. Sandner