Cavity QED with chip-based toroidal microresonators
We report the demonstration of strong coupling between single Cesium atoms and a high-Q chip-based microresonator. Our toroidal microresonators are compact, Si chip-based whispering gallery mode resonators that confine light to small volumes with extremely low losses, and are manufactured in large numbers by standard lithographic techniques. Combined with the capability to couple efficiently light to and from these microresonators by a tapered optical fiber, toroidal microresonators offer a promising avenue towards scalable quantum networks. Experimentally, laser cooled Cs atoms are dropped onto a toroidal microresonator while a probe beam is critically coupled to the cavity mode. When an atom interacts with the cavity, it modifies the resonance spectrum of the cavity, leading to rejection of some of the probe light from the cavity, and thus to an increase in the output power. By observing such transit events while systematically detuning the cavity from the atomic resonance, we determine the maximal accessible single-photon Rabi frequency of Ω_0/2π ≈ (100 ± 24) MHz. This value puts our system in the regime of strong coupling, being significantly larger than the dissipation rates in our system.
Additional Information© 2007 Society of Photo-Optical Instrumentation Engineers (SPIE). We thank M. Eichenfield, K. W. Goh and S. M. Spillane for their contributions to the early stages of this experiment, and T. Carmon, A. Gross and S. Walavalker for their contributions to the current realization. The work of H.J.K. is supported by the National Science Foundation, the Disruptive Technology Office of the Department of National Intelligence, and Caltech. The work of K.J.V. is supported by DARPA, the Caltech Lee Center and the National Science Foundation. B.D., W.P.B. and T.J.K. acknowledge support as Fellows of the Center for the Physics of Information at Caltech. A.S.P. acknowledges support from the Marsden Fund of the Royal Society of New Zealand. The Work of TA is supported by Japan Science and Technology Agency (JST).
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