A curved mirror for atoms was made from an evanescent wave, formed by internal reflection of a quasiresonant laser beam at a curved glass surface. A cold cloud of cesium atoms was dropped onto the mirror and observed to rebound more than 8 times. The mirror size and reflectivity were studied, and reasonable agreement with a simple theory obtained. With 800 mW of laser power and a mirror of 1 mm diameter, we observed up to 73% of the atoms returning after each bounce, the losses being mostly during the free flight between bounces.A curved mirror for atoms was made from an evanescent wave, formed by internal reflection of a quasiresonant laser beam at a curved glass surface. A cold cloud of cesium atoms was dropped onto the mirror and observed to rebound more than 8 times. The mirror size and reflectivity were studied, and reasonable agreement with a simple theory obtained. With 800 mW of laser power and a mirror of 1 mm diameter, we observed up to 73% of the atoms returning after each bounce, the losses being mostly during the free flight between bounces.

Physical Review LettersNov 8, 1993231 citations

Effect of spontaneous emission on the atomic modes in a stable gravitational cavity

G. J. Liston, S. M. Tan, Daniel F. Walls

We calculate the modes in a stable gravitational cavity where the atomic mirror at the bottom of the bounce is caused by an internally reflected intense Gaussian-mode laser beam. In contrast to Wallis, Dalibard, and Cohen-Tannoudji [Appl. Phys. B 54, 407 (1992)], who treated the bottom bouncing mechanism as due to an infinite potential, we include the effect of the exponentially decaying potential caused by the evanescent wave. Nevertheless, we find that above this evanescent wave potential the mode structure corresponds exactly to that obtained using an infinite potential. The allowed energies differ slightly due to the phase change through the evanescent wave. The broadening of the modes due to the damping effects of spontaneous emission was calculated and because of the intrinsic transverse width of the modes was found to depend strongly on energy and transverse excitation, which differs from a simple one-dimensional classical calculation. The finesse and $Q$ of the cavity due to the damping effects of spontaneous emission were also calculated and in contrast to an optical Fabry-P\'erot cavity were found to depend strongly on energy.We calculate the modes in a stable gravitational cavity where the atomic mirror at the bottom of the bounce is caused by an internally reflected intense Gaussian-mode laser beam. In contrast to Wallis, Dalibard, and Cohen-Tannoudji [Appl. Phys. B 54, 407 (1992)], who treated the bottom bouncing mechanism as due to an infinite potential, we include the effect of the exponentially decaying potential caused by the evanescent wave. Nevertheless, we find that above this evanescent wave potential the mode structure corresponds exactly to that obtained using an infinite potential. The allowed energies differ slightly due to the phase change through the evanescent wave. The broadening of the modes due to the damping effects of spontaneous emission was calculated and because of the intrinsic transverse width of the modes was found to depend strongly on energy and transverse excitation, which differs from a simple one-dimensional classical calculation. The finesse and $Q$ of the cavity due to the damping effects of spontaneous emission were also calculated and in contrast to an optical Fabry-P\'erot cavity were found to depend strongly on energy.

Physical Review AOct 1, 19954 citations

Bouncing dynamics of Bose–Einstein condensates under the effects of gravity

Golam Ali Sekh

Physics Letters ADec 22, 201614 citations

Gravity-Driven Bouncing Dynamics of a 2D Bose-Einstein Condensate: Quantum

Gunjan Verma

URSI Regional Conference on Radio Science (URSI-RCRS)Jan 1, 20240 citations

Periodic trajectories of cold atoms in a gravitational cavity

Ifan G. Hughes, Timothy Darlington, Edward A. Hinds

We study the classical dynamics of an atom bouncing on a concave reflector, which is sometimes called a gravitational cavity. Experiments and simulations have previously shown that atoms released from particular heights exhibit anomalously long storage times but no explanations for this have been offered hitherto. Here we show that the stability is associated with orbits where the atom moves on a cyclic trajectory. These have a lower loss rate from the cavity because they explore only a small part of the mirror surface compared with generic trajectories in neighbouring parts of phase space. We identify and classify them.We study the classical dynamics of an atom bouncing on a concave reflector, which is sometimes called a gravitational cavity. Experiments and simulations have previously shown that atoms released from particular heights exhibit anomalously long storage times but no explanations for this have been offered hitherto. Here we show that the stability is associated with orbits where the atom moves on a cyclic trajectory. These have a lower loss rate from the cavity because they explore only a small part of the mirror surface compared with generic trajectories in neighbouring parts of phase space. We identify and classify them.

Journal of Physics B Atomic Molecular and Optical PhysicsJul 11, 200114 citations

Q

of the cavity due to the damping effects of spontaneous emission were also calculated and in contrast to an optical Fabry-P\'erot cavity were found to depend strongly on energy.