Charles Leyder

Interference of coherent polariton beams in microcavities: polarization-controlled optical gates

We demonstrate theoretically that the interaction of two degenerate condensates of exciton-polaritons in microcavities leads to polarization dependent parametric oscillations. The resonant polariton-polariton scattering is governed by the polarization of the condensates and can be fully suppressed for certain polarizations. A polarization controlled solid state optical gate is proposed.

Four wave mixing oscillation in a semiconductor microcavity: generation of two correlated polariton populations.

We demonstrate a novel kind of polariton four wave mixing oscillation. Two pump polaritons scatter towards final states that emit two beams of equal intensity, separated both spatially and in polarization with respect to the pumps. The measurement of the intensity fluctuations of the emitted light demonstrates that the final states are strongly correlated.

Towards quantum correlated polariton modes in semiconductor microcavities

In planar semiconductor microcavities in the strong coupling regime, nonlinear effects such as a Kerr-like effect, parametric fluorescence and parametric oscillation are observed, as a result of the parametric scattering of polaritons. After discussing the basic physical properties of the system and their theoretical description, we report on our experimental demonstration of polariton squeezing in the degenerate scattering configuration (Kerr configuration), and on the generation of correlated polaritons in the nondegenerate configuration. The latter results open the way to the generation of quantum correlated polariton modes.

Generation of quantum correlated photon pairs from a vertical triple microcavity

We study the statistics of twin photons emitted by a vertical triple microcavity. We measured the intensity correlations of the signal and idler by measuring the noise spectra. Quantum correlated photon modes are observed.

Quantum Correlated Polariton Modes in a Semiconductor Vertical Triple Microcavity

This paper presents a semiconductor vertical triple microcavity system consisting of a MBE grown structure, made of three AlGaAs/GaAs lambda-microcavities, including single InGaAs quantum wells. The work investigated an experimental configuration expected to be optimal for generating correlated polariton modes: the pump is at 0deg, resonant with the second branch, and the signal and idler modes are at the same energy and opposite angles on the low energy branch. With this excitation geometry, a high symmetry between signal and idler modes is achieved (same photon content and same linewidth) which ensure maximal correlations. Moreover, the fact that the pump is at normal incidence allows eliminating spurious uncorrelated background noise contributions coming from the resonant Rayleigh scattering of the pump mode. Results show that in the strong light-matter coupling regime (temperature of 4 K, pump excitation 20 mW), the noise spectrum of the difference reveals 5% squeezing, demonstrating the first generation of quantum correlated polariton modes.

Experimental evidence for correlated polaritonic emission from a semiconductor microcavity

In this contribution, a novel geometry is investigated that eliminates the asymmetry between the signal and idler fields,using a nonlinear process that produces signal and idler polaritons with opposite wave vectors, hence the same photon content and the same linewidth, which allows maximal correlations between the signal and idler beams. It is studied theoretically in the Heisenberg-Langevin formalism and is found that perfect quantum correlations can be achieved for the polariton fields. The experimental observation of such nonlinear process is reported. A correlation of about 0.6 between the beams emitted with opposite planar wave vectors us measured. The measured correlations are classical, meaning that the intensity difference between the signal and idler beam is not squeezed. However, these results are very promising in view of the generation of quantum correlated polariton modes.