Near-resonant dark optical lattice with increased occupation
- Institut fuer Laser-Physik, Universitaet Hamburg, Luruper Chaussee 149, D-22761 Hamburg (Germany)
A bichromatic near-resonant dark optical lattice (DOL) with rubidium atoms is demonstrated, which provides confinement in the Lamb-Dicke regime in all spatial dimensions. We apply spatially phase-matched optical potentials for each hyperfine ground state in order to enable improved Sisyphus cooling, undisturbed by optical hyperfine pumping processes. We also explore a method to increase the occupation of the DOL. Initially 2x10{sup 9} rubidium atoms with a temperature of 70 {mu}K and a density of 5x10{sup 10} atoms/cm{sup 3} are prepared in a magneto-optic trap (MOT) and a fraction of 5x10{sup 7} atoms is loaded into a far detuned one-dimensional optical lattice (FOL). Subsequently, the MOT is replaced by the DOL, and the atoms become well localized within the microscopic light-shift potentials at a temperature of 10 {mu}K with a typical density of 3x10{sup 11} atoms/cm{sup 3}. We then apply alternating cycles of free evolution in the FOL and cooling and trapping in the DOL, obtaining a fourfold density increase to 1.2x10{sup 12} atoms/cm{sup 3}--i.e., 7.5% occupation--while maintaining a temperature of 10 {mu}K. In a final adiabatic cooling step we reduce the well depth to 75 times the single-photon recoil energy, which leads to a temperature of 2.8 {mu}K and a phase-space density of 1.7x10{sup -3}. Despite the increased density, no excess heating or collisional losses are observed.
- OSTI ID:
- 20718771
- Journal Information:
- Physical Review. A, Vol. 72, Issue 4; Other Information: DOI: 10.1103/PhysRevA.72.043410; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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