Summary form only given.We present a novel gravito-optical trap (GOT) consisting of a dark hollow-divergent laser beam (DHB) either from a collimated and focused doughnut beam or from the output beam of the LP/sub 01/ mode in a hollow optical fiber. The cold atoms are loaded into the DHB from a magneto-optical trap (MOT). As the atoms bounce in the DHB, they experience Sisyphus cooling and geometrical cooling induced by the blue detuned DHB and a very weak repumping beam propagating downward into the DHB. The coupling of the three-level atom and the DHB forms dressed states.Summary form only given.We present a novel gravito-optical trap (GOT) consisting of a dark hollow-divergent laser beam (DHB) either from a collimated and focused doughnut beam or from the output beam of the LP/sub 01/ mode in a hollow optical fiber. The cold atoms are loaded into the DHB from a magneto-optical trap (MOT). As the atoms bounce in the DHB, they experience Sisyphus cooling and geometrical cooling induced by the blue detuned DHB and a very weak repumping beam propagating downward into the DHB. The coupling of the three-level atom and the DHB forms dressed states.

Conference on Lasers and Electro-OpticsNov 27, 20020 citations

Dark Optical Traps for Cold Atoms

Nir Friedman, Ariel Kaplan, Nir Davidson

Advances in atomic, molecular, and optical physicsJan 1, 200295 citations

Efficient intensity-gradient cooling of atoms in a weak standing-wave hollow-beam trap

Zhengling Wang, Jianping Yin

We propose a trap scheme for cold alkali-metal atoms with an efficient intensity-gradient induced Sisyphus cooling in a weak standing-wave hollow-beam gravito-optical trap, which is composed of the interference of two well collimated, counterpropagating doughnut hollow beams with an intensity difference and a plug beam. We calculate the intensity distribution of the weak standing-wave hollow-beam field and its intensity gradient one, and find that such an optical dipole trap with an extremely high intensity gradient is desirable to realize an efficient intensity-gradient cooling for alkali-metal atoms in the trap. We also calculate the optical potentials, instantaneous dipole forces and spontaneous emission rates for a three-level dressed atom and study the dynamic process of intensity-gradient cooling of $^{87}\mathrm{Rb}$ atoms in the weak standing-wave hollow-beam trap by Monte Carlo simulations. Our study shows that the minimum optical potential at each node in our dipole trap is high enough to trap almost all cold atoms with a temperature of $120\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}$ released from a standard magneto-optical trap, and an ultracold $^{87}\mathrm{Rb}$ atomic sample with a temperature of $\ensuremath{\sim}0.73\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}$ can be obtained in the trap. Starting from this stage, an all-optical Bose-Einstein condensation (BEC) could be realized by using the optical-potential evaporative cooling.We propose a trap scheme for cold alkali-metal atoms with an efficient intensity-gradient induced Sisyphus cooling in a weak standing-wave hollow-beam gravito-optical trap, which is composed of the interference of two well collimated, counterpropagating doughnut hollow beams with an intensity difference and a plug beam. We calculate the intensity distribution of the weak standing-wave hollow-beam field and its intensity gradient one, and find that such an optical dipole trap with an extremely high intensity gradient is desirable to realize an efficient intensity-gradient cooling for alkali-metal atoms in the trap. We also calculate the optical potentials, instantaneous dipole forces and spontaneous emission rates for a three-level dressed atom and study the dynamic process of intensity-gradient cooling of $^{87}\mathrm{Rb}$ atoms in the weak standing-wave hollow-beam trap by Monte Carlo simulations. Our study shows that the minimum optical potential at each node in our dipole trap is high enough to trap almost all cold atoms with a temperature of $120\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}$ released from a standard magneto-optical trap, and an ultracold $^{87}\mathrm{Rb}$ atomic sample with a temperature of $\ensuremath{\sim}0.73\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}$ can be obtained in the trap. Starting from this stage, an all-optical Bose-Einstein condensation (BEC) could be realized by using the optical-potential evaporative cooling.

Physical Review AJul 21, 200610 citations

^{87}\mathrm{Rb}

atoms in the weak standing-wave hollow-beam trap by Monte Carlo simulations. Our study shows that the minimum optical potential at each node in our dipole trap is high enough to trap almost all cold atoms with a temperature of $120\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}$ released from a standard magneto-optical trap, and an ultracold

^{87}\mathrm{Rb}

atomic sample with a temperature of $\ensuremath{\sim}0.73\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}$ can be obtained in the trap. Starting from this stage, an all-optical Bose-Einstein condensation (BEC) could be realized by using the optical-potential evaporative cooling.