G. Dasbach

Parametric oscillation in vertical triple microcavities

Optical parametric oscillation is a nonlinear process that enables coherent generation of ‘signal’ and ‘idler’ waves, shifted in frequency from the pump wave. Efficient parametric conversion is the paradigm for the generation of twin or entangled photons for quantum optics applications such as quantum cryptography, or for the generation of new frequencies in spectral domains not accessible by existing devices. Rapid development in the field of quantum information requires monolithic, alignment-free sources that enable efficient coupling into optical fibres and possibly electrical injection. During the past decade, much effort has been devoted to the development of integrated devices for quantum information and to the realization of all-semiconductor parametric oscillators. Nevertheless, at present optical parametric oscillators typically rely on nonlinear crystals placed into complex external cavities, and pumped by powerful external lasers. Long interaction lengths are typically required and the phase mismatch between the parametric waves propagating at different velocities results in poor parametric conversion efficiencies. Here we report the demonstration of parametric oscillation in a monolithic semiconductor triple microcavity with signal, pump and idler waves propagating along the vertical direction of the nanostructure. Alternatively, signal and idler beams can also be collected at finite angles, allowing the generation of entangled photon pairs. The pump threshold intensity is low enough to envisage the realization of an all-semiconductor electrically pumped micro-parametric oscillator.

Wave-vector-dependent exchange interaction and its relevance for the effective exciton mass in Cu2O

The wave-vector dependence of electron-hole exchange interaction is investigated. For the yellow 1S exciton in

Impact of exciton localization on the optical non-linearities of cavity polaritons

{\mathrm{Cu}}_{2}\mathrm{O}

Optical Parametric Oscillation In A Vertical Triple Microcavity

the exchange is derived up to the order

Optical parametric oscillation in a vertical triple microcavity

{k}^{2}

Polarization controlled parametric oscillation in quasi-one-dimensional microcavities

. The theoretical predictions are verified experimentally by high-resolution absorption experiments. In agreement with theory the fine structure shows a characteristic dependence on the direction of the wave vector. The exchange splitting of the orthoexciton triplet are distinguished from strain-induced perturbations. The exchange gives rise to an isotropic and an anisotropic correction of the effective exciton mass. This can explain the discrepancies in the measurements of the exciton mass in

Pump-and-Probe Studies of Exciton Polaritons in Semiconductor Microcavities: The Impact of Exciton Localization and Cavity Symmetry

{\mathrm{Cu}}_{2}\mathrm{O}

Enhancement of the exciton exchange energy splitting by the confined light field in strained microcavities

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Impact of localization effects on the non-linear optical response of a semiconductor microcavity

Abstract Polaritons in a semiconductor microcavity excited below the free exciton energy have been studied by pump-and-probe experiments. The excitation results in a blue shift of the transmission peak of the lower polariton branch, followed by a strong enhancement and narrowing. These changes are opposite to those caused by high above band gap excitation. The strong differences between resonant and non-resonant excitation result from a different impact of localized excitons and unbound carriers on the quantum well susceptibility. The experimental observations are modeled in the approximation of nonperturbative coupling of the exciton system to the cavity light field.

Tailoring the polariton dispersion by optical confinement: Access to a manifold of elastic polariton pair scattering channels

We report the first realization of a monolithic vertical-cavity, surface emitting micro optical parametric conversion nanostructure, triply resonant with the parametric frequencies, allowing parametric oscillation or amplification with a very low pump power threshold.