Abstract

Most studies on optical lattices¹ are performed with lasers tuned on the red side of a transition connecting a ground level having an angular momentum J toward an excited state of angular momentum J + 1. In this case, the optical potential usually exhibits wells where atoms are located. The typical dynamical behavior of an atom consists of oscillations in a well interrupted by jumps between wells. In the case of a transition connecting a ground level having an angular momentum J toward an excited state of angular momentum J − 1, cooling can also be achieved on the blue side of the transition,² but the lowest potential is flat because of the occurrence of an uncoupled state. When a static magnetic field is added, the optical potential becomes modulated, but it generally exhibits antidots³ rather than wells, as shown in the Fig. 1. As a result, atoms are free to move between the antidots. Actually atom trajectories calculated by numerical simulation show that atoms move by bouncing on the antidots as balls in billiards (Fig. 2). We present experimental and numerical evidence of such trajectories.

© 1998 Optical Society of America