Atom trapping in deeply bound states of a far-off-resonance optical lattice
| Autor: | G. Klose, S. E. Hamann, Poul S. Jessen, D. L. Haycock |
|---|---|
| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | Physical Review A. 55:R3991-R3994 |
| ISSN: | 1094-1622 1050-2947 |
| DOI: | 10.1103/physreva.55.r3991 |
| Popis: | The ac Stark shift ~light shift! arising in laser interference patterns can be used to create stable periodic potentials for neutral atoms. Under appropriate conditions these ‘‘optical lattices’’ will laser cool and trap atoms in individual optical potential wells, with center-of-mass motion in the quantum regime. Experiments have explored a number of such lattice configurations in one, two, and three dimensions, and detailed insight into the dynamics of cooling and trapping has been gained through probe absorption and fluorescence spectroscopy @1#. The possibility of atomic confinement deep in the Lamb-Dicke regime suggests that it is worthwhile to pursue schemes for resolved-sideband Raman cooling @2# and quantum-state preparation @3#, as recently demonstrated for trapped ions. In a standard optical lattice formed by near-resonance light, control of the center-of-mass motion is limited by rapid laser cooling and heating processes that occur at a rate determined by photon scattering. These dissipative processes are readily avoided when the lattice is formed by intense light tuned far from atomic transition. Such far-off-resonance lattices have been used extensively in atom optics as diffraction gratings and lenses @4# and as model systems in which to study quantum chaos @5# and quantum transport @6#. When far-off-resonance optical lattices are used to trap atoms, however, the absence of built-in laser cooling makes it difficult to obtain vibrational excitation and confinement comparable to the near-resonance case. Accordingly, experiments on faroff-resonance lattices have so far achieved low vibrational excitation only by allowing the majority of vibrationally excited atoms to escape @7#. We demonstrate here a loading scheme, in which cesium atoms are first cooled and trapped in a near-resonance lattice, and then adiabatically transferred to a superimposed far-off resonance lattice. Immediately following transfer we achieve trapping parameters comparable to the near-resonance case, with a mean vibrational excitation as low as n ¯ ’0.3, and a typical rms position spread of Dz’l/20. Based on the lattice parameters we calculate an off-resonance photon scattering rate of order 10 3 s 21 .W e |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|