Sensitive Detection of Individual Neutral Atoms in a Strong Coupling Cavity QED System
Pengfei Zhang, Yuchi Zhang, Gang Li, Jinjin Du, Yanfeng Zhang, Yanqiang Guo, Junmin Wang, Tiancai Zhang, Weidong Li · Chinese Physics Letters · 2011
We experimentally demonstrate real-time detection of individual cesium atoms by using a high-finesse optical micro-cavity in a strong coupling regime. A cloud of cesium atoms is trapped in a magneto-optical trap positioned at 5 mm above the micro-cavity center. The atoms fall down freely in gravitation after shutting off the magneto-optical trap and pass through the cavity. The cavity transmission is strongly affected by the atoms in the cavity, which enables the micro-cavity to sense the atoms individually. We detect the single atom transits either in the resonance or various detunings. The single atom vacuum-Rabi splitting is directly measured to be Ω = 2π × 23.9 MHz. The average duration of atom-cavity coupling of about 110 μs is obtained according to the probability distribution of the atom transits.