Bulletin of the American Physical Society
A miniature linear RF ion trap
Jonathan Magnolia Gilligan, Christopher R. Monroe, David J. Wineland
Abstract
We report on development of a miniature linear rf ion trap and preliminary efforts to trap and laser-cool {sup 24}Mg{sup +} ions. This trap has a radial dimension of 50 {mu}m, one tenth the size of our previous trap. The rms confinement of a trapped ion scales as R{sup -2}, where R is the trap radius, so tight confinement of ions is possible at a modest rf voltage. Although the three-dimensional trapping potential for our trap cannot be calculated analytically, it can be described in terms of dimensionless parameters, measured by studying macroscopic charged particles in a much larger model of the trap. We expect that with this trap it will be possible to achieve secular frequencies high enough for resolved-sideband cooling of light ions using allowed dipole transitions. This will make it much easier to perform experiments on the quantum motion of trapped ions. This trap uses a two-wire design rather than the more common four-wire one, so the trap electrodes occlude a much smaller solid angle than either a four-wire linear trap or the more common quadrupole trap. Thus, it will be possible to couple optical devices, such as high-finesse cavities, much more efficiently to trapped ions.