Optical bistability and collective behavior of atoms trapped in a high-Q ring cavity

摘要

We study the collective motion of atoms confined in an optical lattice operating inside a high-finesse ring cavity. A simplified theoretical model for the dynamics of the system is developed upon the assumption of adiabaticity of the atomic motion. We show that in a regime where the light shift per photon times the number of atoms exceeds the linewidth of the cavity resonance, the otherwise tiny retroaction of the atoms upon the light field becomes a significant feature of the system. As a result dispersive optical bistability can arise and the lattice positions is determined by the strength of the atom-cavity coupling rather than by the phases of the incoupled light beams. Solving the complete set of classical equations of motion confirms these findings, however, additional nonadiabatic phenomena are predicted, such as, for example, self-induced radial breathing oscillations. We compare these results with experiments involving laser-cooled Rb-85 atoms trapped in an optical lattice inside a ring cavity with a finesse of 1.8x10(5). Our observations are in excellent agreement with our theoretical predictions.