Crossover to 2D in a double-evanescent wave trap

Abstract
We report the preparation of a dense gas of cesium atoms at the crossover to two-dimensionality in a highly anisotropic surface trap that is realized with two evanescent light waves. Temperatures as low as 100 nK are reached with 20.000 atoms at a phase-space density close to 0.1. The lowest quantum state in the tightly confined direction is populated by more than 60%. The system offers intriguing prospects for future experiments on degenerate quantum gases in two dimensions.