Resolved-Sideband Raman Cooling to the Ground State of an Optical Lattice

 

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S.E. Hamann, D.L. Haycock, G. Klose, P.H. Pax, I.H. Deutsch* and P.S. Jessen Optical Sciences Center, University of Arizona, Tucson, AZ 85721 *Center for Advanced Studies, Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131
 

We trap neutral Cs atoms in a two-dimensional optical lattice and cool them close to the zero-point motion by resolved-sideband Raman cooling. Sideband cooling occurs via transitions between the vibrational manifolds associated with a pair of magnetic sublevels and the required Raman coupling is provided by the lattice potential itself. We obtain mean vibrational excitations nx ny 0.01, corrensponding to a population ~98% in the vibrational ground state. Atoms in the ground state of an optical lattice provide a new system in which to explore quantum state control and subrecoil laser cooling.
 

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Enhanced laser cooling and state preparation in an optical lattice with magnetic field

 

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D.L. Haycock, S.E. Hamann, G. Klose, G.Raithel* and P.S. Jessen Optical Sciences Center, University of Arizona, Tucson, AZ 85721 *National Institute of Standards and Technology, PHYS A167, Gaithersburg, MD 20899
 

We demonstrate that weak magnetic fields can significantly enhance laser cooling and sate preparation of Cs atoms in a one-dimensional optical lattice. A field parallel to the lattice axis increases the vibrational ground state population of the stretched state |m=F> to 28%. A transverse field ireduces the kinetic temperature. Quantum Monte-Carlo simulations agree with the experiment, and predict 45% ground state population for optimal parallel and transverse fields. Our results show that coherent mixing and local energy relaxation play important roles in laser cooling of large-F atoms.
 

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Quantum State Control in Optical Lattices

 

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Ivan H. Deutsch Center for Advanced Studies, Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 Poul S. Jessen Optical Sciences Center, University of Arizona, Tucson, AZ 85721
 

We study the means to prepare and coherently manipulate atomic wave packets in optical lattices, with particular emphasis on alkalis in the far-detuned limit. We derive a general, basis independent expression for the lattice potential operator, and show that its off-diagonal elements can be tailored to couple the vibrational manifolds of separate magnetic sublevels. Using these couplings one can evolve the state of a trapped atom in a quantum coherent fashion, and prepare pure quantum states by resolved-sideband Raman cooling. We explore the use of atoms bound in optical lattices to study quantum tunneling and the generation of macroscopic superposition states in a double-well potential. Far-off-resonance optical potentials lend themselves particularly well to reservoir engineering via well controlled fluctuations in the potential, making the atom/lattice system attractive for the study of decoherence and the connection between classical and quantum physics.
 

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