Erlangen 2018 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 62: Poster: Quantum Optics and Photonics V

Q 62.60: Poster

Thursday, March 8, 2018, 16:15–18:15, Redoutensaal

Strong Coupling between Photons via a four-level N-type atom — •Bo Wang, Nicolas Tolazzi, Jonas Neumeier, Christoph Hamsen, Gang Li, Tatjana Wilk, and Gerhard Rempe — Max Planck Institute of Quantum Optics, Hans-Kopfermann-Str. 1, 85748 Garching, Germany

Four-level N-type atomic systems have been investigated for effects like the electromagnetically induced absorption (EIA) and cross-phase modulation (XPM) when interacting with classical light fields[1]. Despite the giant nonlinearity, the interaction strengths are negligible at the level of individual quanta. However with the strong light matter coupling provided by cavity quantum elecrodynamics, a significant interaction between single photons can be reached. Here we report on an experiment where the photons of two light fields are strongly coupled via a single four-level N-type atom. The fields drive two modes of an optical cavity, which are strongly coupled to two separate transitions. A control laser drives one transition’s ground state to the other transition’s excited state, the inner transition of the N-type atom. It induces a tunable coupling between the modes and results in a doubly nonlinear energy-level structure of the photon-photon-atom system. The strong correlation between the light fields is observed via photon-photon blocking and photon-photon tunneling. With this new system, nondestructive counting of photons and heralded n-photon sources might be within reach.
Li S, Yang X, Cao X, Zhang C, Xie C, Wang H, Phys. Rev. Lett. 101(7)(2008) 073602.