Benoît Marie Joseph Deveaud

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

We report on spinor polariton interactions in GaAs based microcavities. This investigation is carried out by means of heterodyne polarized pump-probe spectroscopy. We show the dependence of the energy renormalization of the lower and upper polariton resona ...

We report on noise-induced spin ordering in a collective quasiparticle system: spinor stochastic resonance. Synergetic interplay of a polarization-modulated signal and a polarization noise allows us to switch coherently between the two metastable states of ...

We resonantly excite exciton-polariton states confined in cylindrical traps. Using a homodyne detection setup, we are able to image the phase and amplitude of the confined polariton states. We evidence the excitation of vortex states, carrying an integer a ...

We present a detailed study of the luminescence at 3.42 eV usually observed in a-plane epitaxial lateral overgrowth (ELO) GaN grown by hydride vapor phase epitaxy on r-plane sapphire. This band is related to radiative recombination of excitons in a commonl ...

Wide quantum wells, where the energy spacing between the first two energy levels is lower than the energy of the polar optical phonon, could represent the ideal condition to obtain a population inversion and the production of infrared lasers. On the other hand in these quantum wells the efficiency of carrier-carrier scattering is increasing with the width of the well and can produce a relatively quick relaxation of carriers in the first subband. In this work we present a detailed and systematic joint theore

Using an angle-resolved heterodyne four-wave-mixing technique, we probe the low momentum excitation spectrum of a coherent polariton gas. The experimental results are well captured by the Bogoliubov transformation which describes the transition from single ...

The longitudinal spatial hole burning (LSHB) in gain-clamped semiconductor optical amplifiers (GCSOA's) is investigated by means of a numerical model, which is based on position-dependent rate equations for the carrier density and the propagation equations for the optical power, The simulation results show that the carrier densities are nonuniformly distributed within the active layer of GCSOA's, The nonuniformity can be large, especially for high currents and optical signal powers near the saturation. It i

Measurements of spontaneous emission from InGaAsP semiconductor optical amplifiers provide information on both the carrier density and temperature. By spatially resolving the light emitted along the active layer of the device, we find evidence of longitudinal spatial hole burning which results from amplified spontaneous emission in the structure and is modified by the injected optical signal. Under injection, we also observe pronounced asymmetry of the amplified spontaneous emission intensity from the two f

We study the carrier-density-dependent recombination dynamics in m-plane InGaN/GaN multiple quantum wells in the presence of n-type background doping by time-resolved photoluminescence. Based on Fermi's golden rule and Saha's equation, we decompose the rad ...

Using reflectivity and picosecond time-resolved photoluminescence, we have studied the intrinsic optical properties of negatively charged excitons in modulation doped CdTe quantum wells. In emission, we observe simultaneously a low energy exponential tail in the charged exciton spectral line and a linear increase of its radiative lifetime with temperature. In absorption, we find a consistent decrease of the charged exciton oscillator strength with temperature. For low electron concentrations these observati

Time-resolved cathodoluminescence at 27 K has been performed on a-plane GaN grown by epitaxial lateral overgrowth. We detail the relaxation and recombination mechanisms of excitons [free or bound to neutral donors, or bound to I1-type basal stacking faults ...

We study the emission properties of confined polariton states in shallow zero-dimensional traps under nonresonant excitation. We evidence several relaxation regimes. For slightly negative photon-exciton detuning, we observe a nonlinear increase of the emis ...

Second-order time correlations of polaritons have been measured across the condensation threshold in a CdTe microcavity. The onset of Bose-Einstein condensation is marked by the disappearance of photon bunching, demonstrating the transition from a thermal- ...

Interactions among excitons, trions, and electrons are studied in CdTe modulation-doped quantum wells. These many-body interactions are investigated through the nonlinear dynamical properties in the excitonic complexes using time and spectrally resolved pump and probe techniques. This study is performed as a function of temperature and densities of excitons, trions, and electrons. The results reveal that the nonlinearities induced by trions differ from those induced by excitons and moreover they are mutuall

We have observed marked oscillations in the time-resolved photoluminescence of a semiconductor microcavity under non-resonant excitation conditions. Hot excitons, created with an ultrashort light pulse, rapidly relax into polaritons in the cavity with a large in-plane momentum K. Shortly after illumination, above a certain excitation power, the polaritons accumulate into an energy trap at the bottom of the dispersion and the light emission, governed by final-state stimulated scattering, starts at K similar

Experimental demonstration of optical speedup at transparency (OSAT) has been performed on a 1 mm long semiconductor optical amplifiers (SOA). OSAT is a recently proposed scheme that decreases the recovery time of an SOA while maintaining the available gain. It is achieved by externally injecting into the SOA the beam of a separate high power laser at energies around the transparency point. Even though the experimental conditions were not optimal, a beam of 100 mW decreases the recovery time by a third when

We demonstrate a novel all-optical spatial Light modulator capable of megahertz modulation rates. It is based on the quantum-confined Stark effect, but the modulating electric field is entirely photogenerated by strongly asymmetric photocarrier transfer in GaAs/AlAs layers. In a nonoptimized sample, cw optical excitation of approximately 50 W/cm(2) created a 30-kV/cm electric field, inducing a 9-meV exciton red shift at room temperature. Under pulsed excitation the photogenerated electric field can be switc

We report on the dynamics of confined zero-dimensional polaritons. We excite resonantly discrete polariton states optically with a tailored picosecond laser pulse and observe their emission time resolved in the two-dimensional k space or real space. We are ...

We report on the nonlinear optical dynamical properties of excitonic complexes in CdTe modulation-doped quantum wells, due to many-body interactions among excitons, trions, and electrons. These were studied by time and spectrally resolved pump-probe experiments. The results reveal that the nonlinearities induced by trions differ from those induced by excitons, and in addition they are mutually correlated. We propose that the main source of these subtle differences comes from the Pauli exclusion-principle th

We study the wave functions of exciton polaritons trapped in the elliptical traps of a patterned microcavity. A homodyne detection setup with numerical off-axis filtering allows us to retrieve the amplitude and the phase of the wave functions. Doublet stat ...

Benoît Marie Joseph Deveaud

Chat with Graph Search

Heterodyne spectroscopy of polariton spinor interactions

Spinor stochastic resonance

Selective photoexcitation of confined exciton-polariton vortices

Exciton localization on basal stacking faults in a-plane epitaxial lateral overgrown GaN grown by hydride vapor phase epitaxy

Carrier-carrier interaction and fast intersubband scattering in wide GaAs quantum wells

From Single Particle to Superfluid Excitations in a Dissipative Polariton Gas

Longitudinal spatial hole burning and associated nonlinear gain in gain-clamped semiconductor optical amplifiers

Direct observation of longitudinal spatial hole burning in semiconductor optical amplifiers with injection

Carrier-density-dependent recombination dynamics of excitons and electron-hole plasma in m-plane InGaN/GaN quantum wells

Radiative behavior of negatively charged excitons in CdTe-based quantum wells: A spectral and temporal analysis

Low-temperature time-resolved cathodoluminescence study of exciton dynamics involving basal stacking faults in a-plane GaN

Nonlinear relaxation of zero-dimension-trapped microcavity polaritons

Second-order time correlations within a polariton Bose-Einstein condensate in a CdTe microcavity

Many-body interaction evidenced through exciton-trion-electron correlated dynamics

Oscillatory behaviour in the nonlinear emission of semiconductor microcavities

Optical speedup at transparency of the gain recovery in semiconductor optical amplifiers

All-Optical Spatial Light-Modulator with Megahertz Modulation Rates

Spatial dynamics of confined semiconductor microcavity polaritons

Interacting many-body systems in quantum wells: Evidence for exciton-trion-electron correlations

Phase-resolved imaging of confined exciton-polariton wave functions in elliptical traps