François Morier-Genoud

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We present a novel semiconductor structure in which 0D polaritons coexist with 2D microcavity polaritons. Spatial trapping of the 2D microcavity polaritons results from the confinement of their photonic part in a potential well, consisting of an adjustable ...

In this experimental work, we optically excite the eigenmodes of an elliptical resonator in a semiconductor micro-cavity. Using a pulsed excitation, we create a superposition of eigenmodes, and image the time evolution of the coherent emission pattern. Oscillations between vortex and anti-vortex states are observed, and remarkably well described within the Poincar sphere representation for an eigenmode containing an orbital angular momentum. A semiconductor quantum well is embedded in the microcavity struct

The incorporation of In in the growth of crescent-shaped In0.12Ga0.88As quantum wires embedded in (AlAs)(4)(GaAs)(8) superlattice barriers is studied in atomic detail using cross-sectional scanning tunneling microscopy. It is found that the In distribution in both the surface and the first subsurface layer can be atomically resolved in the empty- and filled-state images, respectively. Strong In segregation is seen at the InGaAs/GaAs interfaces, but neither an expected enhancement of the In concentration at

We report on the effect of noise on the characteristics of the bistable polariton emission system. The present experiment provides a time-resolved access to the polariton emission intensity. We evidence the noise-induced transitions between the two stable ...

We study an asymmetric double InGaAs quantum well using optical two-dimensional coherent spectroscopy. The collection of zero-quantum, one-quantum, and two-quantum two-dimensional spectra provides a unique and comprehensive picture of the double well coher ...

Exciton polaritons have been shown to be an optimal system in order to investigate the properties of bosonic quantum fluids. We report here on the observation of dark solitons in the wake of engineered circular obstacles and their decay into streets of qua ...

We present the results of a detailed time-resolved luminescence study carried out on a very high quality InGaAs quantum well sample where the contributions at the energy of the exciton and at the band edge can be clearly separated. We perform this experiment with a spectral resolution and a sensitivity of the setup, allowing us to keep the observation of these two separate contributions over a broad range of times and densities. This allows us to directly evidence the exciton formation time, which depends o

Optical parametric oscillator including a semiconductor microcavity being configured to spatially localize polaritons of at least three quantized polariton energy levels to effect an optical parametric oscillation. ...

The optical nonlinearity of a GaAs/AlAs periodic layered structure was experimentally investigated for the first time. The shift of the reflectivity peak with increasing intensity was observed. A reflectivity contrast of about 10:1 was obtained by varying the incident intensity. Hysteresis loops due to the response delay of both the electronic and the thermal nonlinearity were observed. All-optical logic operations were also demonstrated. A further improvement of the structure may lead to a new type of opti

We experimentally demonstrate a technique for the generation of optical beams carrying orbital angular momentum using a planar semiconductor microcavity. Despite being isotropic systems with no structural gyrotropy, semiconductor microcavities, because of ...

We used optical pumping by the Vanderbilt free-electron laser and the technique of internal photoemission to measure with high accuracy the conduction-band discontinuity of semiconductor heterojunction interfaces. The experiment is the first application to our knowledge of a free-electron laser to interface research.

Quantum wire heterostructures, such as V- and T-shaped wires, are very promising candidates for low-threshold lasing. A crucial issue is the excitonic vs. free-carrier nature of the radiative recombination. Here, we report on magnetophotoluminescence studies of GaAs and InGaAs V-shaped wires that allow to discriminate different regimes of radiative recombination.

We show a double path mechanism for the formation of charged excitons (trions); they are formed through bi- and trimolecular processes. This directly implies that both negatively and positively charged excitons coexist in a quantum well, even in the absenc ...

Fabrication and characterization of a current-injected InGaAs-GaAs quantum-wire gain-coupled distributed feedback (DFB) laser operating at 77 K at a wavelength of 923 nm are presented, Threshold current densities in broad area lasers were measured to be as low as 160 A/cm(2), The side-mode suppression ratio at twice threshold is 35 dB. A 4-mu m rib waveguide device has a threshold of 14 mA, The patterning process for the second-order DFB grating fabricated with deep UV holography and wet-chemical etching is

We report on a bulk GaAlAs mirror which is used as a saturable absorber for subpicosecond pulse generation around 835 nm. The mirror consists of a 200 nm layer of bulk GaAlAs (with approximately 5% Al content) which is grown on a linear Bragg mirror and is used as a laser end mirror. The incorporation of the bulk GaAlAs mirror into a synchronously pumped styryl-9 dye laser leads to a significant mode locking improvement and pulse shortening. Optimum operation of the laser is obtained for wavelengths near th

The influence of magnetic field on confined exciton-polariton modes inside a semiconductor microcavity is discussed. The three-dimensional confinement for exciton-polaritons is achieved by the mesa structures confining the photonic part of polaritons. We o ...

In this work, we report on the first realization of multi-valued spin switching in the solid-state. We investigate the physics of spinor bistability with microcavity polaritons in a trap. Spinor interactions lead to special bistability regimes with decoupled thresholds for spin-up and spin-down polaritons. This allows us to establish state-of-the-art spin switching operations. We evidence polarization hysteresis and determine appropriate conditions to achieve spin multistability. For a given excitation cond

We present the optical tomography of the probability density of quasiparticles, the microcavity polaritons, confined in three dimensions by cylindrical traps. Collecting the photoluminescence emitted by the quasimodes under continuous nonresonant laser exc ...

Raman spectroscopy has been used to measure phonons in GaAs v-groove quantum wire structures containing (001) and (111) GaAs/AlAs superlattice barrier regions. Resonance enhancement permits the identification of modes in different regions of the structure, and the measured phonon frequencies provide structural information which shows clear evidence of GaAs migration during growth from (001) surfaces into the grooves. Confined and interface phonons with large in-(111) plane wavevectors are observed. (C) 1996

We report the experimental observation of optical bistable switching in a combined distributed-feedback/Fabry-Perot structure. The sample had a high switching contrast with almost zero reflectivity in the on-state. A turnoff time as short as 4 ns was measured. The threshold power for bistability was about 2 mW. Bistable switching with the memory effect and a potential application for all-optical signal regeneration were demonstrated.

François Morier-Genoud

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Zero dimensional exciton-polaritons

Coherent oscillations between polariton vortex and anti-vortex states in an elliptical resonator

Indium Distribution in Ingaas Quantum Wires Observed with the Scanning Tunneling Microscope

Effect of a noisy driving field on a bistable polariton system

Coherent Excitonic Coupling in an Asymmetric Double InGaAs Quantum Well Arises from Many-Body Effects

Soliton Instabilities and Vortex Street Formation in a Polariton Quantum Fluid

Determination of the exciton formation in quantum wells from time-resolved interband luminescence

Near infrared twin photon source

All-Optical Reflectivity Tuning and Logic Gating in a GaAs/AlAs Periodic Layered Structure

Spin-to-orbital angular momentum conversion in semiconductor microcavities

Interface Measurements of Heterojunction Band Lineups with the Vanderbilt Free-Electron Laser

Magnetic-field effects in the luminescence of V-shaped quantum wires

Dynamics of trion formation in GaAs quantum wells

Distributed feedback gain-coupled lasers based on InGaAs quantum-wire arrays

Bulk GaAlAs Mirror as a Saturable Absorber for Subpicosecond Pulse Generation around 835 Nm

Magnetic Field Induced Redistribution of Exciton-Polariton Density on Confined Modes

Multi-Valued Spin Switch in a Semiconductor Microcavity

Probability density optical tomography of confined quasiparticles in a semiconductor microcavity

Resonant Raman scattering from phonons in GaAs/(GaAs)(m)(AlAs)(n) quantum wire structures

All-Optical Bistable Switching and Signal Regeneration in a Semiconductor Layered Distributed-Feedback/Fabry-Perot Structure