Efficient, Indirect Transverse Laser Cooling of a Fast Stored Ion Beam

Oscillating Coulomb chain in a storage ring

The dynamic behavior of a bunched one-dimensional crystalline beam is studied theoretically. It is shown that, owing to the existence of momentum dispersion, a Coulomb chain traveling in a storage ring performs a complex periodic oscillation whenever it is exposed to a longitudinal radio-frequency force. The equations of motion are derived to predict the oscillation pattern in an arbitrary lattice structure. The validity of the present theory is confirmed through multiparticle simulations. Various features of an oscillating string beam, such as the lattice-parameter dependence of the orbit, the stability, and critical line density, etc., are also discussed.

Three-dimensional crystalline ion beams

We report on the experimental realization of two- and three-dimensional crystalline ion beams in the rf quadrupole storage ring PALLAS (LMU, Munich). At a beam energy around 1 eV the phase transition to the Coulomb ordered state is identified by a sudden decrease of the spatial width and of the velocity spread of the beam. The focusing conditions required to attain crystalline beams up to structures of helices surrounding a string are systematically investigated and related to the situation in typical heavy ion storage rings.

Optical trapping and manipulation of neutral particles using lasers

The techniques of optical trapping and manipulation of neutral particles by lasers provide unique means to control the dynamics of small particles. These new experimental methods have played a revolutionary role in areas of the physical and biological sciences. This paper reviews the early developments in the field leading to the demonstration of cooling and trapping of neutral atoms in atomic physics and to the first use of optical tweezers traps in biology. Some further major achievements of these rapidly developing methods also are considered.