Vacuum Rabi splitting with a single quantum dot in a photonic crystal nanocavity

Yoshie, T.
Scherer, A.
Hendrickson, J.
Khitrova, G.
Gibbs, H. M.
Rupper, G.
Ell, C.
Shchekin, O. B.
Deppe, D. G.

¹Electrical Engineering, California Institute of Technology, Pasadena, California 91125, USA
²Optical Sciences Center, The University of Arizona, Tucson, Arizona 85721, USA
³Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, USA

Received 7 August; accepted 19 October 2004; doi:10.1038/nature03119.

Correspondence and requests for materials should be addressed to G. K.

Nature 432(7014):p 200-203, November 11, 2004.

Cavity quantum electrodynamics (QED) systems allow the study of a variety of fundamental quantum-optics phenomena, such as entanglement, quantum decoherence and the quantum-classical boundary. Such systems also provide test beds for quantum information science. Nearly all strongly coupled cavity QED experiments have used a single atom in a high-quality-factor (high-Q) cavity. Here we report the experimental realization of a strongly coupled system in the solid state: a single quantum dot embedded in the spacer of a nanocavity, showing vacuum-field Rabi splitting exceeding the decoherence linewidths of both the nanocavity and the quantum dot. This requires a small-volume cavity and an atomic-like two-level system. The photonic crystalslab nanocavity-which traps photons when a defect is introduced inside the two-dimensional photonic bandgap by leaving out one or more holes-has both highQand small modal volumeV,as required for strong light-matter interactions. The quantum dot has two discrete energy levels with a transition dipole moment much larger than that of an atom, and it is fixed in the nanocavity during growth.