Browsing by Author "Story, J.G."

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    Adiabatic cooling of atoms by an intense standing wave
    (American Physical Society, 1992) Chen, Jian; Story, J.G.; Tollett, J.J.; Hulet, Randall G.; Rice Quantum Institute
    Lithium atoms channeled in the nodes of an intense standing-wave radiation field are cooled to near the recoil limit by adibatically reducing the radiation intensity. The final momentum distribution has a narrow component with a root-mean-squared momentum of 2ħk in one dimension, where ħk is the momentum of a radiation-field photon. The data are compared with the results of a Monte Carlo simulation using a two-level atom model. This process may be useful for cooling and increasing the phase-space density of atoms confined in a magnetic trap.
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    Evolution of atomic motion in an intense standing wave
    (American Physical Society, 1993) Chen, Jian; Story, J.G.; Hulet, Randall G.; Rice Quantum Institute
    We have investigated the effect of the dipole force and its fluctuation on the motion of Li atoms in an intense, one-dimensional, near-resonant standing light wave. The duration of the interaction of the atoms with the standing wave was varied from several tens of spontaneous-emission lifetimes to several hundreds. For a standing-wave frequency blue detuned from resonance, diffusive heating can dominate the time-averaged dissipative dipole force so that there is no steady-state momentum distribution. However, for sufficiently large blue detunings, the rate of diffusion is so slow that the resulting distribution approaches a quasisteady state. For red detunings, the diffusion is balanced with the force and a true steady state is achieved. We apply a Monte Carlo method based on the density-matrix equations in the dressed-state representation to simulate the atomic motion. The dynamics of atom channeling is discussed.
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    Observation of velocity-tuned multiphoton "Doppleron" resonances in laser-cooled atoms
    (American Physical Society, 1990) Tollett, J.J.; Chen, J.; Story, J.G.; Ritchie, N.W.M.; Bradley, C.C.; Hulet, Randall G.; Rice Quantum Institute
    An atomic beam of Li was transversely cooled using an intense standing-wave radiation field. A dramatic change in the transverse velocity distribution was observed. Structure in the resulting velocity distribution was found to be due to velocity-tuned multiphoton ‘‘Doppleron’’ resonances. The force due to seven-photon resonances is clearly resolved in the data. The data are in good agreement with theoretical predictions.
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    Realization of a measurement of a ‘‘weak value’’
    (American Physical Society, 1991) Ritchie, N.W.M.; Story, J.G.; Hulet, Randall G.; Rice Quantum Institute
    We present the first realization of a measurement of a ‘‘weak value,’’ a concept recently introduced by Aharonov, Albert, and Vaidman (AAV). Our experiment uses a birefringent crystal to separate the two linear-polarization components of a laser beam by a distance small compared to the laser-beam waist. This ‘‘weak measurement’’ is followed by a strong measurement which translates the centroid of the beam by a distance far larger than the birefringence-induced separation. In addition, we present data corresponding to orthogonal initial and final states, for which the weak value is not defined. This interference effect may have application in the amplification and detection of weak effects.