Publications de Vincenzo Savona

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We propose a single-photon source based on a pair of weakly nonlinear optical cavities subject to a one-directional dissipative coupling. When both cavities are driven by mutually coherent fields, sub-Poissonian light is generated in the target cavity even ...

By comparing a kinetic and a thermal-equilibrium theory of polariton Bose-Einstein condensation, we study under what conditions the dynamical condensation under steady-state non-resonant pumping can approach thermal equilibrium. In particular, we study the ...

Single photon emitters often rely on a strong nonlinearity to make the behavior of a quantum mode susceptible to a change in the number of quanta between one and two. In most systems, the strength of nonlinearity is weak, such that changes at the single qu ...

We report on the experimental realization of ultra-high quality factor (Q) designs of the L3-type photonic crystal nanocavity. Based on genetic optimization of the positions of few nearby holes, our design drastically improves the performance of the conven ...

We study the system of two quantum dots lying on the central plane of a planar semiconductor microcavity. By solving the full Maxwell problem, we demonstrate that the rate of resonant excitation transfer between the two dots decays as d(-12) as a function ...

We study exciton and biexciton spectra in disordered semiconductor quantum wires by means of nanophotoluminescence spectroscopy. We demonstrate a close link between the exciton localization length along the wire and the occurrence of a biexciton spectral l ...

Luminescence spectra of V-groove GaAs/AlGaAs quantum wires are investigated by spatially resolved photoluminescence (PL) spectroscopy using a low temperature scanning near-field optical microscope (SNOM). The statistical analysis of these spectra in terms of the autocorrelation function reveals the presence of level repulsion. We find that the comparison between the experimental autocorrelation curve and the theoretical one obtained from the simulation of PL spectra, assuming for each exciton state a Lorent

It is shown that noncentrosymmetric materials with bulk second-order nonlinear susceptibility can be used to generate strongly antibunched radiation at an arbitrary wavelength, solely determined by the resonant behavior of suitably engineered coupled micro ...

We theoretically study the emission statistics of a weakly nonlinear photonic dimer during coherent oscillations. We show that the phase and population dynamics allow to periodically meet an optimal squeezing condition resulting in a strongly nonclassical ...

Photonic crystal point-defect cavities were fabricated in a GaN free-standing photonic crystal slab. The cavities are based on the popular L3 design, which was optimized using an automated process based on a genetic algorithm, in order to maximize the qual ...

We use a rate equation model in order to reproduce the dynamics of two-dimensional excitons and free carriers in a time resolved photoluminescence experiment. We investigate the dynamics of the exciton formation from free electron-hole pairs, and the evolution of Is excitons within their band. The interaction of excitons and free carriers with optical and acoustic phonons is considered. The shape of the time resolved photoluminescence signal is considerably different in the case of acoustic or optical phono

Slow light has a variety of applications, in particular for enhanced nonlinear effects like four-wave mixing and high-harmonic generation. Here, we propose a photonic crystal coupled-cavity waveguide with an ultracompact arrangement of the constituent cavi ...

The experimental investigation of spontaneously created vortices is of utmost importance for the understanding of quantum phase transitions towards a superfluid phase, especially for two-dimensional systems that are expected to be governed by the Berezinski-Kosterlitz-Thouless physics. By means of time-resolved near-field interferometry we track the path of such vortices, created at random locations in an exciton-polariton condensate under pulsed nonresonant excitation, to their final pinning positions impo

The polariton Hamiltonian for a quantum well embedded in a cavity of finite width is derived. The exciton-light interaction is formulated in second quantization and the photon self-interaction term A2 is included. The importance of the A2 term turns out to be relevant in the case of large values of the cavity width. By solving the equation of motion the dispersion relations for upper and lower polaritons are found. A comparison is made with existing measurements of polariton absorption peaks. The limit of i

We investigate the physics of coherent polaritons in a double-well configuration under a resonant pumping. For a continuous-wave pump, bistability and self-pulsing regimes are identified as a function of the pump energy and intensity. The response to an ad ...

The nonequilibrium dynamics of a two-dimensional electron-hole gas is studied in the regime of strong and resonant pumping of the exciton resonance. The Coulomb collision rates are consistently determined by taking into account the light-induced coherence of the two-band system that leads to a dressing of the carrier spectral functions. The light dressing dramatically reduces the Coulomb scattering efficiency. Results are presented for Rabi oscillations in the time domain and dynamical Stark splitting in th

We present a theoretical model of the time-resolved excitonic photoluminescence in quantum wires. We study the role of disorder and of the exciton-free-carrier interaction on the temperature dependence of the photoluminescence lifetime. We find that at low temperature the exciton population is not thermalized in disordered quantum wires and that the lifetime is mainly determined by the localization length of the exciton. However, for large localization lengths or high enough temperatures the exciton populat

The outstanding progress in nanostructure fabrication and cooling technologies allows what was unthinkable a few decades ago: bringing single-mode mechanical vibrations to the quantum regime. The coupling between photon and phonon excitations is a natural ...

We study an array of coupled optical cavities in the presence of two-photon driving and dissipation. The system displays a critical behavior similar to that of a quantum Ising model at finite temperature. Using the corner-space renormalization method, we c ...

We derive the effective Bose Hamiltonian for a system of interacting excitons applying the Usui transformation. The fermionic nonlinearities are consistently included, leading to a density dependent correction to the kinetic Hamiltonian and to a saturation of the exciton oscillator strength. The exciton-exciton interaction potentials due to the Coulomb interaction are calculated, accounting for the spin dependence. Starting from the effective Hamiltonian, we obtain the excitonic Bloch equations. As a first

Vincenzo Savona

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Single photons from dissipation in coupled cavities

Towards thermal equilibrium in the Bose-Einstein condensation of microcavity polaritons

Single Photons from Coupled Quantum Modes

Genetically designed L3 photonic crystal nanocavities with measured quality factor exceeding one million

Ultralong-range radiative excitation transfer between quantum dots in a planar microcavity

Localization-dependent photoluminescence spectrum of biexcitons in semiconductor quantum wires

Photoluminescence spectra and level repulsion in quantum wires

Unconventional photon blockade in doubly resonant microcavities with second-order nonlinearity

Nonclassical statistics from a polaritonic Josephson junction

Gallium nitride L3 photonic crystal cavities with an average quality factor of 16 900 in the near infrared

Photoluminescence and carrier dynamics in GaAs quantum wells

Wide-band slow light in compact photonic crystal coupled-cavity waveguides

Probing the Dynamics of Spontaneous Quantum Vortices in Polariton Superfluids

Quantum-Theory Of Quantum-Well Polaritons In Semiconductor Microcavities

Coherent dynamics and parametric instabilities of microcavity polaritons in double-well systems

Strongly driven exciton resonances in quantum wells: Light-induced dressing versus Coulomb scattering

Modeling the photoluminescence lifetime in realistic quantum wires

Remote macroscopic entanglement on a photonic crystal architecture

Quantum Critical Regime in a Quadratically Driven Nonlinear Photonic Lattice

Excitonic Bloch equations for a two-dimensional system of interacting excitons