Strongly correlated photons on a chip

Nature Photonics (Impact Factor: 32.39). 08/2011; 6(2). DOI: 10.1038/nphoton.2011.321
Source: arXiv


Optical non-linearities at the single-photon level are key ingredients for
future photonic quantum technologies. Prime candidates for the realization of
strong photon-photon interactions necessary for implementing quantum
information processing tasks as well as for studying strongly correlated
photons in an integrated photonic device setting are quantum dots embedded in
photonic crystal nanocavities. Here, we report strong quantum correlations
between photons on picosecond timescales. We observe (a) photon antibunching
upon resonant excitation of the lowest-energy polariton state, proving that the
first cavity photon blocks the subsequent injection events, and (b) photon
bunching when the laser field is in two-photon resonance with the polariton
eigenstates of the second Jaynes-Cummings manifold, demonstrating that two
photons at this color are more likely to be injected into the cavity jointly,
than they would otherwise. Together,these results demonstrate unprecedented
strong single-photon non-linearities, paving the way for realizing a
single-photon transistor or a quantum optical Josephson interferometer.

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Available from: K. Hennessy, Oct 09, 2015
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    • "The focus of these studies is made on a possibility of making fewphoton devices (transistors, mirrors, switchers, transducers , etc.) as building blocks for either all-photonic or hybrid quantum devices. While a number of few-photon emitters based on single molecules, diamond color centers and quantum dots are available nowadays [8],[9], an understanding of the extreme quantum regime of a few-photon scattering in a 1D fiber or transmission line [10],[11] should be supplemented by microscopic studies of scattering of a coherent light (e.g., generated by a laser driving) off an emitter in a confined 1D geometry. This is the main motivation of the present work. "
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    Physical Review A 04/2015; 91(6). DOI:10.1103/PhysRevA.91.063841 · 2.81 Impact Factor
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    ABSTRACT: We have performed ultrafast pump–probe experiments on a GaAs–AlAs microcavity with a resonance near 1300 nm in the "Original" telecom band. We concentrate on ultimate-fast optical switching of the cavity resonance that is measured as a function of pump-pulse energy. We observe that, at low pump-pulse energies, the switching of the cavity resonance is governed by the instantaneous electronic Kerr effect and is achieved within 300 fs. At high pump-pulse energies, the index change induced by free carriers generated in the GaAs start to compete with the electronic Kerr effect and reduce the resonance frequency shift. We have developed an analytic model that pre-dicts this competition in agreement with the experimental data. To this end, we derive the nondegenerate two-and three-photon absorption coefficients for GaAs. Our model includes a new term in the intensity-dependent refractive index that considers the effect of the probe-pulse intensity, which is resonantly enhanced by the cavity. We calculate the effect of the resonantly enhanced probe light on the refractive index change induced by the electronic Kerr effect for cavities with different quality factors. By exploiting the linear regime where only the electronic Kerr effect is observed, we manage to retrieve the nondegenerate third-order nonlinear susceptibility χ …3† for GaAs from the cavity resonance shift as a function of pump-pulse energy.
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    ABSTRACT: We present detuning-dependent spectral and decay-rate measurements to study the difference between spectral and dynamical properties of single quantum dots embedded in micropillar and photonic-crystal cavities. For the micropillar cavity, the dynamics is well described by the dissipative Jaynes-Cummings model, while systematic deviations are observed for the emission spectra. The discrepancy for the spectra is attributed to coupling of other exciton lines to the cavity and interference of different propagation paths towards the detector of the fields emitted by the quantum dot. In contrast, quantitative information about the system can readily be extracted from the dynamical measurements. In the case of photonic crystal cavities we observe an anti crossing in the spectra when detuning a single quantum dot through resonance, which is the spectral signature of strong coupling. However, time-resolved measurements reveal that the actual coupling strength is significantly smaller than anticipated from the spectral measurements and that the quantum dot is rather weakly coupled to the cavity. We suggest that the observed Rabi splitting is due to cavity feeding by other quantum dots and/or multiexcition complexes giving rise to collective emission effects.
    New Journal of Physics 10/2012; 15(2). DOI:10.1088/1367-2630/15/2/025013 · 3.56 Impact Factor
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