Abstract

The laser manipulation of neutral particles has started important developments for biophysical and biochemical applications with the realization of traps for biological cells using a properly focused single laser beam. Such a trap, suggested for the first time by Ashkin,¹ is based on the large electric field created by a laser beam in order to induce an electric dipole moment in the particle to be trapped. If the laser frequency is lower than the absorption frequencies of the trapped particle, the induced electric dipole moment is in phase with the applied electric field, and the particle reaches the state with the lowest energy at the position where the electric field has the maximum value.

© 1994 IEEE