Cavity QED with ultracold atoms on an atom chip.

摘要

Many of the advances in cavity quantum electrodynamics (cavity QED) in the last decade have come by controlling the position and motion of atoms coupled to high finesse optical resonators with greater precision. Our experiment uses clouds of ultracold atomic gas confined in the miniaturized magnetic traps of a microfabricated atom chip to achieve high precision positioning of atoms relative to the optical standing wave mode of a high finesse Fabry-Perot cavity. The atom chip consists of micropatterned copper wires buried in a micromachined silicon substrata Up to several thousand ultracold 87 Rb atoms are placed in the mode of our Fabry-Perot optical cavity, which attains the single-atom, strong-coupling regime of cavity QED for the D2 transition of 87Rb. We study the atom-cavity system in the dispersive coupling limit, where the cavity resonance frequency is far detuned from the atomic transition. In this limit the mechanical effects on the atoms of the light used to probe the cavity are explored. We report observations of optical histability in this system as the mechanical potential from probing light induces a shift in the position atomic cloud and thus a shift in the spatially dependent atom-cavity coupling. The design, construction, and operation of this combined cavity QED atom chip are also described.