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.

Download full-text


Available from: K. Hennessy,
  • Source
    • "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. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We provide a complete and exact quantum description of coherent light scattering in a one-dimensional multi-mode transmission line coupled to a two-level emitter. Using recently developed scattering approach we discuss transmission properties, power spectrum, the full counting statistics and the entanglement entropy of transmitted and reflected states of light. Our approach takes into account spatial parameters of an incident coherent pulse as well as waiting and counting times of a detector. We describe time evolution of the power spectrum as well as observe deviations from the Poissonian statistics for reflected and transmitted fields. In particular, the statistics of reflected photons can change from sub-Poissonian to super-Poissonian for increasing values of the detuning, while the statistics of transmitted photons is strictly super-Poissonian in all parametric regimes. We study the entanglement entropy of some spatial part of the scattered pulse and observe that it obeys the area laws and that it is bounded by the maximal entropy of the effective four-level system.
    Physical Review A 04/2015; 91(6). DOI:10.1103/PhysRevA.91.063841 · 2.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nichtlineare Wechselwirkungen zwischen einzelnen Lichtquanten, den Photonen, werden zentraler Bestandteil zukünftiger optischer Quantentechnologien sein. Unserer Arbeitsgruppe an der ETH Zürich gelang es kürzlich, ein hochgradig nichtlineares optisches System, bestehend aus einem Quantenpunkt in einem nanophotonischen Resonator, zu realisieren und daran starke Quantenkorrelationen zwischen gestreuten Photonen nachzuweisen. Ein derartiges System könnte als Einzelphotonen-Transistor in einem optischen Computerchip zum Einsatz kommen.
    Physik in unserer Zeit 03/2012; 43(2):59-60. DOI:10.1002/piuz.201290027
  • Source
    [Show abstract] [Hide abstract]
    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.
    Journal of the Optical Society of America B 09/2012; 29(9):2630-2642. DOI:10.1364/JOSAB.29.002630 · 1.97 Impact Factor
Show more