We have examined the mechanical effects of light on a three level atom. A single excited state decays to two long-lived ground states. One of the transitions is driven by an intense standing wave, while the other is driven by a traveling wave. We examine this system using analytical and computational techniques, and compare with experimental observations of {sup 7}Li. In the absence of the second ground state and laser field, the atom can be cooled by the familiar two level dipole force. In the three level system, the dipole force cooling mechanism is still present, and can be considerably enhanced. As in the two level system, the cold three level atoms are channeled, or localized in space with respect to the standing wave. In the three level case, the atoms can be channeled in the second ground state, even though that state interacts only with the traveling wave laser, which has no spatial structure. We will discuss applications of the three level cooling force to atomic beam slowing experiments, and the attainment of ultra-cold final temperatures using adiabatic cooling.We have examined the mechanical effects of light on a three level atom. A single excited state decays to two long-lived ground states. One of the transitions is driven by an intense standing wave, while the other is driven by a traveling wave. We examine this system using analytical and computational techniques, and compare with experimental observations of {sup 7}Li. In the absence of the second ground state and laser field, the atom can be cooled by the familiar two level dipole force. In the three level system, the dipole force cooling mechanism is still present, and can be considerably enhanced. As in the two level system, the cold three level atoms are channeled, or localized in space with respect to the standing wave. In the three level case, the atoms can be channeled in the second ground state, even though that state interacts only with the traveling wave laser, which has no spatial structure. We will discuss applications of the three level cooling force to atomic beam slowing experiments, and the attainment of ultra-cold final temperatures using adiabatic cooling.

Bulletin of the American Physical SocietyMay 1, 19930 citations

Radiation forces on a three-level atom in the high-order Bessel beams

Zhengling Wang, Yin Jian-Ping

The general expressions of the average dissipative and dipole forces acting on a Λ-configuration three-level atom in an arbitrary light field are derived by means of the optical Bloch equations based on the atomic density matrix elements, and the general properties of the average dissipative and dipole forces on a three-level atom in the linearly-polarized high-order Bessel beams (HBBs) are analysed. We find a resonant property (with two resonant peaks) of the dissipative force and a non-resonant property (with two pairs of non-resonant peaks) of the dipole force on the three-level atom, which are completely different from those on the two-level atom. Meanwhile we find a saturation effect of the average dissipative force in the HBB, which comes from the saturation of the upper-level population. Our study shows that the general expressions of the average dissipative and dipole forces on the three-level atom will be simplified to those of the two-level atom under the approximation of large detuning. Finally, we study the axial and azimuthal Doppler cooling of atoms in 1D optical molasses composed of two counter-propagating HBBs and discuss the azimuthal influence of the HBB on the Doppler cooling limit. We also find that the Doppler limit of atoms in the molasses HBB is slightly below the conventional Doppler limit of ħΓ(2κ B ) due to the orbital angular momentum l ħ of the HBB.The general expressions of the average dissipative and dipole forces acting on a Λ-configuration three-level atom in an arbitrary light field are derived by means of the optical Bloch equations based on the atomic density matrix elements, and the general properties of the average dissipative and dipole forces on a three-level atom in the linearly-polarized high-order Bessel beams (HBBs) are analysed. We find a resonant property (with two resonant peaks) of the dissipative force and a non-resonant property (with two pairs of non-resonant peaks) of the dipole force on the three-level atom, which are completely different from those on the two-level atom. Meanwhile we find a saturation effect of the average dissipative force in the HBB, which comes from the saturation of the upper-level population. Our study shows that the general expressions of the average dissipative and dipole forces on the three-level atom will be simplified to those of the two-level atom under the approximation of large detuning. Finally, we study the axial and azimuthal Doppler cooling of atoms in 1D optical molasses composed of two counter-propagating HBBs and discuss the azimuthal influence of the HBB on the Doppler cooling limit. We also find that the Doppler limit of atoms in the molasses HBB is slightly below the conventional Doppler limit of ħΓ(2κ B ) due to the orbital angular momentum l ħ of the HBB.

Chinese Physics BJul 1, 200810 citations

Dipole cooling using an optical memory

Péter Horák

Feb 1, 20100 citations

Dipole force cooling of multilevel atoms

Charles A. Sackett

A theoretical discussion of laser cooling of multilevel atomic systems using intense, blue detuned laser beams is given. A method based on matrix continued fractions is presented, which enables the efficient calculation of the semi-classical force on a multilevel system. The method is applied to a three-level system driven by one standing wave and one travelling wave. The force curves obtained exhibit strong cooling features. Cooling of the three-level system is simulated using the fully quantum mechanical Monte Carlo wave function technique. The simulation predicts efficient cooling to sub-Doppler temperatures. The three-level model is related to a multilevel cooling experiment performed on $\\sp7$ Li. The experimental results are found to be in reasonable agreement with the three-level model. However, a comparison of the simulation and experiment for a two-level atomic system reveals significant discrepancies, which raises questions about the model and experiment.A theoretical discussion of laser cooling of multilevel atomic systems using intense, blue detuned laser beams is given. A method based on matrix continued fractions is presented, which enables the efficient calculation of the semi-classical force on a multilevel system. The method is applied to a three-level system driven by one standing wave and one travelling wave. The force curves obtained exhibit strong cooling features. Cooling of the three-level system is simulated using the fully quantum mechanical Monte Carlo wave function technique. The simulation predicts efficient cooling to sub-Doppler temperatures. The three-level model is related to a multilevel cooling experiment performed on $\\sp7$Li. The experimental results are found to be in reasonable agreement with the three-level model. However, a comparison of the simulation and experiment for a two-level atomic system reveals significant discrepancies, which raises questions about the model and experiment.

Jan 1, 19940 citations

\\sp7

Li. The experimental results are found to be in reasonable agreement with the three-level model. However, a comparison of the simulation and experiment for a two-level atomic system reveals significant discrepancies, which raises questions about the model and experiment.