Marc-André Dupertuis

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We analyze in depth the eigenmodes symmetry of the vectorial electromagnetic wave equation with discrete symmetry, using a recently developed maximal symmetrization and reduction scheme leading to an automatic technique which decomposes every mode into its ...

Quantum dots (QDs) of high symmetry (e.g., C3v) have degenerate bright exciton states, unlike QDs of C2v symmetry, making them intrinsically suitable for the generation of entangled photon pairs. Deviations from C3v symmetry are detected in real QDs by pol ...

We study statistical signatures of composite bosons made of two fermions by extending number states to these quantum particles. Two-particle correlations as well as the dispersion of the probability distribution are analyzed. We show that the particle comp ...

To test the validity of replacing a composite fermion by an elementary fermion, we calculate the transition rate from a state made of one free electron and one trion to a similar electron-trion pair, through the time evolution of such a pair induced by Cou ...

Generalized Snell-Descartes and Fresnel laws are derived for harmonic inhomogeneous plane waves that are incident upon a static interface between two continuous absorbing dielectric media that are macroscopically characterized by their electric and magnetic permittivities and their conductivities. A coordinate-free formalism based on complex vector algebra is used to carry out all discussions. Surprisingly, the usual complex Snell-Descartes laws for reflection and refraction and Fresnel laws for polarizatio

We have directly measured the carrier temperature in semiconductor optical amplifiers (SOAs) via spontaneous emission and we demonstrate an unexpectedly high carrier temperature. The direct correlation of the temperature increase with the carrier density suggests Auger recombination as the main heating mechanism. We have developed a model based on rate equations for the total energy density of electrons, holes, and longitudinal-optical phonons. This model allows us to explain the thermal behavior of carrier

V groove GaAs/AlGaAs quantum wires are investigated by spatially resolved photoluminescence spectroscopy using a low-temperature scanning near- field optical microscope. The spectra along the wires feature several sharp emission lines, which are understood as the emission from exciton states localized in inhomogeneities of the confining potential. It is expected that these exciton states spatially overlap and that their energies are correlated, which leads to level repulsion. The statistical analysis of the

A general formalism for the maximal symmetrization and reduction of fields (MSRFs) is proposed and applied to wave functions in solid-state nanostructures. Its primary target is to provide an essential tool for the study and analysis of the electronic and ...

Energy balance and reciprocity relations are studied for harmonic inhomogeneous plane waves that are incident upon a stack of continuous absorbing dielectric media that are macroscopically characterized by their electric and magnetic permittivities and their conductivities. New cross terms between parallel electric and parallel magnetic modes are identified in the fully generalized Poynting vector. The symmetry and the relations between the general Fresnel coefficients are investigated in the context of ene

We experimentally verify the link existing between entanglement and the amount of wave-particle duality in a bipartite quantum system with superconducting qubits in the IBM Q quantum computer. We consider both pure and mixed states, and study the influence ...

We investigate the properties of electronic states and optical transitions in hexagonal GaAs quantum dots within Al0.3Ga0.7As nanowires, grown in axial direction [111]. Such dots are particularly interesting due to their high degree of symmetry. A streamli ...

Negatively and positively charged excitons are identified in the spatially resolved photoluminescence spectra of quantum wires. We demonstrate that charged excitons are weakly localized in disordered quantum wires. As a consequence, the enhancement of the ...

High symmetry epitaxial quantum dots (QDs) with three or more symmetry planes provide a very promising route for the generation of entangled photons for quantum information applications. The great challenge to fabricate nanoscopic high symmetry QDs is furt ...

The adiabatic approximation is used to describe the electron states of weakly-one-dimensional quantum wires. A clear order is evidenced in the longitudinal optical (LO) phonon mediated transition rates with respect to the quantum numbers of the confined states involved. The average single electron relaxation time from an excited level is shown either to increase or, surprisingly; to decrease as a function of the initial energy. The relaxation of an excited population is dynamically simulated, showing the wi

The electron states of weakly-one-dimensional quantum wires are computed using the adiabatic approximation in the framework of the k . p theory and the envelope-function approximation. The computed transition rates of electrons from one confined state to any other, mediated by the longitudinal optical (LO) phonons, are clearly ordered with respect to the quantum numbers of the states provided by the adiabatic approximation. The average single electron relaxation time from an excited level is shown to either

The properties of V-shaped optical dielectric waveguides are investigated in detail using a vectorial finite element method. The fundamental modes exhibit extremely tight, heart shaped near field patterns. The maximum intensity of the fundamental mode is found to be vertically shifted with respect to the geometrical center of the waveguide. Fundamental and higher order mode properties are extensively studied, including mode patterns, dispersion curves and polarization properties. The local mode polarization

We investigate the charge current that is optically injected by interference between one- and two-photon excitation in the presence of excitonic effects. We consider a realistic V-shaped quantum wire excited slightly below the band gap by two simultaneous ...

We review the research done in recent years in our group on the effects of nanostructure symmetry, and outline its relevance both for nanostructure physics and for computations of their electronic and optical properties. The exemples of C3v and C2v quantum ...

The formation mechanisms, structure and optoelectronic properties of Ga(In)As/(Al)GaAs quantum dot (QD) heterostructures grown by organometallic chemical vapor deposition on patterned (111)B GaAs substrates are reviewed. With this approach, it is possible to prepare high-quality semiconductor QDs whose position on a substrate is precisely controlled via a pre-growth photolithography step. The dots are formed at the center of an inverted, tetrahedral pyramid and are surrounded by distinct, low-dimensional ba

We have measured the ultrafast simultaneous cross-gain and laser mode dynamics in a gain-clamped semiconductor amplifier perturbed by an intense detuned 150 fs pump pulse. Besides relaxation oscillations, we demonstrate the instantaneous formation of a dark pulse in the laser mode that repeats itself with a period given by the cavity round-trip time. The dark pulse sequence subsequently decays into two-mode beating and is shown to weakly cross modulate the amplifier gain. To describe dark-pulse formation a

Marc-André Dupertuis

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Analysis of photonic crystal defect modes by maximal symmetrization and reduction

Fine structure of exciton complexes in high-symmetry quantum dots: Effects of symmetry breaking and symmetry elevation

Role of fermion exchanges in statistical signatures of composite bosons

Effect of fermionic components on trion-electron scattering

Generalization of Complex Snell-Descartes and Fresnel Laws

Hot phonons and Auger related carrier heating in semiconductor optical amplifiers

Exciton relaxation and level repulsion in GaAs/AlxGa1-xAs quantum wires

Maximal symmetrization and reduction of fields: Application to wave functions in solid-state nanostructures

Generalized Energy-Balance and Reciprocity Relations for Thin-Film Optics

Evidence of the entanglement constraint on wave-particle duality using the IBM Q quantum computer

Symmetries and optical transitions of hexagonal quantum dots in GaAs/AlGaAs nanowires

Enhancement of the binding energy of charged excitons in disordered quantum wires

Spectral signatures of high-symmetry quantum dots and effects of symmetry breaking

Electron relaxation by LO phonons in quantum wires

Electron relaxation by LO phonons in quantum wires: An adiabatic approach

Vectorial electromagnetic modes in V-shaped dielectric waveguides with application to quantum wire devices

Optical injection of charge current in quantum wires: oscillations induced by excitonic effects

Nanostructure Symmetry: Relevance for Physics and Computing

Site- and energy-controlled pyramidal quantum dot heterostructures

Observation of dark-pulse formation in gain-clamped semiconductor optical amplifiers by cross-gain modulation