We present a semiclassical theory that can describe the centre-of-mass motion of a neutral atom in a strongly coupled cavity field. We show that a cavity-assisted cooling mechanism can lead to efficient loading of an atom into a wavelength size optical microtrap.
We present a systematic semiclassical model for the simulation of the dynamics of a single two-level atom strongly coupled to a driven high-finesse optical cavity. From the Fokker-Planck equation of the combined atom-field Wigner function we derive stochastic differential equations for the atomic motion and the cavity field. The corresponding noise sources exhibit strong correlations between the atomic momentum fluctuations and the noise in the phase quadrature of the cavity field. The model provides an effective tool to investigate localisation effects as well as cooling and trapping times. In addition, we can continuously study the transition from a few photon quantum field to the classical limit of a large coherent field amplitude.
We present a systematic semiclassical model for the simulation of the dynamics of a single two-level atom strongly coupled to a driven high-finesse optical cavity.From the Fokker-Planck equation of the combined atom-field Wigner function we derive stochastic differential equations for the atomic motion and the cavity field.The corresponding noise sources exhibit strong correlations between the atomic momentum fluctuations and the noise in the phase quadrature of the cavity field.The model provides an effective tool to investigate localization effects as well as cooling and trapping times.In addition, we can continuously study the transition from a few-photon quantum field to the classical limit of a large coherent field amplitude.
A theoretical study is carried out for the cavity cooling of a V-type three-level atom in a high-finesse optical cavity driven by a light field. The dynamical equations are obtained by a semiclassical approach, which is based on the joint atom-field Wigner function of both the motional atomic degrees of freedom and cavity field, including the spontaneous emission and cavity decay. The numerical results show that the highest cooling rate of the V-type three-level atom can be increased 10 times that of a two-level atom. In addition, the cooling rate can be significantly improved by modulating parameters.
We calculate the loading efficiency and cooling rates in a bichromatic optical microtrap, where the optical potentials are generated by evanescent waves of cavity fields at a dielectric-vacuum interface. The cavity modified nonconservative dynamic light forces lead to efficient loading of the atoms as well as cooling without the need for spontaneous emission. Steady-state temperatures well below the trap depth, reaching the motional quantum regime, yield very long capturing times for a neutral atom.
We analyze the dynamics leading to radiative cooling of an atomic ensemble confined inside an optical cavity when the atomic dipolar transitions are incoherently pumped and can synchronize. Our study is performed in the semiclassical regime and assumes that cavity decay is the largest rate in the system dynamics. We identify three regimes characterizing the cooling. At first hot atoms are individually cooled by the cavity friction forces. After this stage, the atoms' center-of-mass motion is further cooled by the coupling to the internal degrees of freedom while the dipoles synchronize. In the latest stage dipole-dipole correlations are stationary and the center-of-mass motion is determined by the interplay between friction and dispersive forces due to the coupling with the collective dipole. We analyze this asymptotic regime by means of a mean-field model and show that the width of the momentum distribution can be of the order of the photon recoil. Furthermore, the internal excitations oscillate spatially with the cavity standing wave forming an antiferromagnetic-like order.