Atom-Field Interaction Studies in AN Atomic Beam.

Miguel Orszag

Qiming Li

The interaction of a beam of two level atoms with a standing wave laser field has been the subject of extensive investigation in recent times. A standing wave perpendicular to an atomic beam allows the manipulation of the transverse velocity distribution. The interaction of an atomic beam with a strong standing wave laser field has been systematically investigated by both theoretical simulation and experiment in this thesis. We have developed a numerical model based on a continued fraction solution for the light pressure forces to simulate the near perpendicular interaction of an atomic beam with a strong standing wave laser field. The reshaping of the transverse spatial profile of an atomic beam by a perpendicular, near resonant, standing wave laser field is investigated for red detunings using a longitudinal velocity selective detection system. The experimental dependence of the reshaped profile on the longitudinal and transverse atomic velocities agrees well with a continued fraction solution for the light force. In particular, a regime is found where channelling of the atoms near the antinodes of the standing wave produces a central peak in the spatial distribution of the atomic beam in the far field which have also been observed elsewhere.

Weiping Zhang, Daniel F. Walls

We employ a vector quantum field theory to describe the interaction of a coherent atomic beam with a standing-wave laser field. The coherent atomic beam is assumed to be composed of degenerate bosonic atoms. We derive a nonlinear Schr\"odinger equation to describe the diffraction of the coherent atomic beam through the standing-wave laser field in the adiabatic regime of interaction of atoms with a light wave. Under appropriate conditions, we find that the standing-wave laser field acts as a quantum nonlinear atomic beam splitter for a coherent atomic beam. The quantum correlations in the nonlinear atomic beam splitter are analyzed and the analogy to quantum correlations of nonclassical light in an optical Kerr-type medium is discussed.

Miguel Orszag

Qiming Lj, Ian C. M. Littler, K. G. H. Baldwin +2 more

The interaction of a beam of two level atoms with a standing wave laser light field has been the subject of extensive investigation in recent times. A standing wave perpendicular to an atomic beam enables the manipulation of the transverse velocity distribution. We have developed a numerical model using a continued fraction solution for the light pressure forces1 to simulate the interaction of an atomic beam with a strong laser field. Using this model, the behaviour of the atoms with small transverse velocity (kv1 « Γ) in a strong standing laser field has been systematically investigated.2