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We present a new compact fiber optic system which together with a high brightness single-photon source facilitates the generation of multi-photon entangled states. Two and three entangled photon states have been prepared and measured.

We generate highly pure quantum states of light in a coherent superposition of zero, one, and two photons. Such states are generated by coherently driving electrically-controlled QD-microcavity devices with a resonant laser pulses. © 2019 The Author(s)

We have devised an all-fiber scheme for the creation of multipartite entanglement of photons of arbitrary number. A quantum dot single photon source was utilized and entanglement of four photons was demonstrated.

Tuning the band structure of photonic Dirac materials allows engineering novel optical properties. We use photonic honeycomb lattices to tailor semi-Dirac photons that combine zero, finite and infinite effective masses.

I present our last results on AlGaAs photonic devices emitting non-classical states of light at room temperature: monolithic integration of heralded single photon sources and beam splitters and engineering of frequency qudits and non-Gaussian entanglement.

A single semiconductor quantum dot in a microcavity is shown to filter single photon Fock states. The device presents non-linearity threshold of 0.3 photons and strongly suppresses the multiphoton components of an incident coherent beam.

We demonstrate the monolithic integration of a heralded single photon AlGaAs source and a 50/50 beamsplitter. A cross correlation measurement on the beamsplitter output ports reveals the quantum nature of the generated light.

We report on the polarization tomography of a resonantly-driven quantum-dot cavity-QED device. A single quantum-dot excitonic transition induces a macroscopic rotation on the polarization of the reflected photons, with a polarization purity remaining above 84%.

We demonstrate the single-photon Fock state filtering on a QD-micropillar cavity system. By performing resonant-excitation measurements, we observe an optical nonlinearity at the sub-photon scale and 80% single-photons in the reflected light intensity.

Phonons degrade the photon indistinguishability in solid-state single-photon devices. Here we demonstrate the robustness of the indistinguishability of non-postselected single-photons against phonon-induced sources of decoherence in coupled quantum dot-cavity devices working under strong Purcell regime.

We explore the possibility to implement a solid state quantum network based on semiconductor quantum dots in microcavities. The cavity enhanced light matter coupling allows creating a very efficient interface between the quantum dot and the optical far field. We deterministically position a single quantum dot in a connected pillar microcavity combined with a p-i-n junction and fabricate tunable ultrabright single photon sources. The collection efficiency is shown to exceed 60% and the indistinguishability of photons successively emitted by one device is in the 80-97% range depending on the excitation conditions. The quantum interference of photons emitted by two remote devices is shown to be greatly enhanced by the acceleration of spontaneous emission. Finally, we explore the possibility to store the quantum information on a longer time scale using the spin states of a hole in a quantum dot. We demonstrate the non-destructive measurement of a single spin by monitoring the spin dependent rotation of polarization of a probe beam: a polarization rotation of ±6° is observed depending on the spin state.

Light-matter coupling in a cavity results in a ladder of states with splittings determined by the coupling strength. We observe the higher ladder rungs in a semiconductor microcavity using multiquantum coherent optical photocurrent spectroscopy.

Entangling a single spin to the polarization of a single incoming photon, generated by an external source, would open new paradigms in quantum optics: this relies on the possibility that a single spin induces a macroscopic rotation of a photon polarization. Up to now, however, the observed polarization rotations were limited to a few 10−3 degrees. Here we report the amplification by three orders of magnitude of the spin-photon interaction, using a single hole spin in a quantum dot-pillar cavity system. A polarization rotation by ±6° is obtained when the spin is optically initialized in either the up or down state. We finally show how quantum measurements and quantum entanglement can be implemented with realistic cavity-QED devices.

We present a technique based on a two-photon absorption process. We coherently inject polaritons in planar or pillar microcavities, being in resonance and with a well defined in plane wavevector (k) and show polariton laser.

A generalization of Turing patterns, originally developed for chemical reactions, to patterns in quantum fluids can be realized with microcavity polaritons. Theoretical concepts of formation and control, together with experimental observations, will be presented.

Recent advances in quantum dot based quantum technology are presented: scalable fabrication of bright sources of single photons or entangled photon pairs, optical non-linearities at the few photon scales and first implementations of quantum gates.

Polaritons in semiconductor microcavities can form patterns analogous to conventional Turing patterns, including two-spot and hexagon far field patterns. We present theoretical concepts of pattern formation and control, together with experimental observations.

Pulse generation from single-section Fabry-Perot InAs/GaAs edge-emitting quantum dot lasers is reported at 1.3μm. Mode-locking performances of the devices are studied as function of injection current and optical spectrum shape.

We present GaAs disk optomechanical resonators that combine high-Q whispering gallery optical modes, GHz mechanical modes, and sub-wavelength optomechanical volume inducing extreme cooperativity. We report on the uncommon nonlinear optomechanical dynamics of these systems.

Time-resolved terahertz absorption by intra-excitonic 1s-2p transitions traces the matter part of cavity polaritons while they cool into a condensed phase. The population dynamics close to the zero-momentum state is correlated with simultaneous angle-resolved photoluminescence.

We report on Type-I CW SHG in AlGaAs/AlOx waveguides, with pump wavelength around 1.55 μm and 2.8% W-1 conversion efficiency. This result is encouraging toward integrated spontaneous parametric downconversion in the telecom range.

InAlAs/GaAlAs quantum dots are studied using transmission electron microscopy, photoluminescence. This systems appear as promising materials for laser and non-linear optics in the visible/near infrared range, particularly as a focusing Kerr-like medium for pattern formation.