Toroidal Optical Dipole Traps for twe

A. A. Lipovka, Miguel A. Cervantes

Tim Freegarde, Kishan Dholakia

G. Edward Marti, Ryan Olf, Gabriel Dunn +1 more

Ewan M. Wright, Jochen Arlt, Kishan Dholakia

We theoretically investigate the use of red-detuned Laguerre-Gaussian (LG) laser beams of varying azimuthal mode index for producing toroidal optical dipole traps in two-dimensional atomic Bose-Einstein condensates. Higher-order LG beams provide deeper potential wells and tighter confinement for a fixed toroid radius and laser power. Numerical simulations of the loading of the toroidal trap from a variety of initial conditions are also given.

Galina A. Nemova

Leif Humbert, Mark A. Baker, D. Sigle +5 more

We report on our progress towards realization of a toroidal trap for Bose-Einstein condensates (BECs) of 87Rb using a time-averaged optical dipole potential. To achieve BEC we utilize a 20 W laser operating at 1064 nm to form an optical dipole trap in which we evaporatively cool the gas . Loading of the dipole trap is achieved by overlapping the dipole beams with a standard magnetic optical trap. Evaporative cooling is first performed in a single beam trap, followed by compression and additional confinement with a second orthogonal beam. This prevents stagnation of the evaporative cooling cycle, and allows the gain of 105 in phase space density necessary to achieve quantum degeneracy.