Abstract

The resolution obtainable in classical as well as modern spectroscopy has always been limited by the finite velocity distribution of atoms. Even in experiments using nonlinear first-order Doppler-free techniques it plays an important and limiting role through second-order Doppler broadening and transit time broadening. Successful demonstrations of cooling and even stopping of thermal atomic beams have recently been reported using the radiation pressure of laser beams. This technique can also be used for cooling fast ion beams stored in heavy ion storage rings. In the present experiment a 4-m long beamline limits the interaction time of a 100-keV Ne beam with a collinear resonant laser beam to 4 μs. This only allows scattering of the order of 100 photons on each atom, corresponding to an acceleration of <0.5 eV. However, with the vast increase in interaction time in going from the present single-pass scheme to experiments on stored ions a dramatic increase in the influence and capability of the laser cooling is achieved. Laser cooling of heavy stored ions is thus predicted to lead to crystallization of the beam.

© 1987 Optical Society of America