Publications de Romuald Houdré

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The project data will be organised in the following folder system : One main folder for the each subproject : GaN nonlinear optics and Optical trapping Each folder is organised in the following sub-folder system (not all may be used), each with a readme- ...

We experimentally investigate the effect of residual disorder on the dispersion curve of light near a band edge. A Fourier space imaging technique accurately distinguishes the propagating regime from evanescent regime in planar photonic crystal. (C) 2009 Optical Society of America

A reproducible and robust techique of contacting GaAs/GaAlAs heterostructures using an evaporated AuGeNi alloy has been developed. The behavior of the electrical contacts to the two-dimensional electron gas has been studied in the quantum Hall regime. Contact resistance values of typically 10-50 m-OMEGA are obtained which are stable with time and thermal cycling. This type of contact is therefore well suited to be used for precision measurements of the quantized Hall resistance.

We use a Fourier-space imaging technique relying on outcoupling grating probes to study the coupled mode interaction and dispersion properties of guided modes in silicon-on-insulator codirectional couplers. Our approach allows us to measure the mode splitt ...

The authors address feature-size dependence in Ar/Cl2 chemically assisted ion beam etching (CAIBE) in the context of the fabrication of photonic crystal (PhC) structures. They systematically investigate the influence of various parameters such a ...

We experimentally observe a sizable and reversible spectral tuning of the resonances of a two-dimensional photonic crystal microcavity induced by the introduction of a subwavelength size glass tip. The comparison between experimental near-field data, colle ...

Making use of bound states in the continuum, we present experimental results on efficient second harmonic generation in photonic crystal cavities supporting doubly-resonant modes. The second harmonic emission is a vortex beam with radial polarization and e ...

We study the coherent optical response of a very high-finesse microcavity with a single quantum well by means of degenerate subpicosecond pump-probe spectroscopy. The dynamics of the ac Stark effect versus Pump intensity is investigated upon tuning the empty-cavity;mode-below and above the exciton transition energy, at the exciton continuum onset. The evolution from a simple dynamical excitonic shift to a dynamical splitting is clearly observed in both eases. The qualitative, agreement with numerical calcul

Valence- and conduction-band offsets can be induced at GaAs(100) polar homojunctions by means of ultrathin Si intralayers. The microscopic interface dipole responsible for the creation of such offsets can be varied by changing the Si intralayer thickness; the consequently variable band discontinuities represent a tunable parameter with potential applications in band-gap engineering. Even though the existence and the direction of these discontinuities are in agreement with theoretical predictions, the existi

Suspended epitaxial gallium nitride (GaN) on silicon (Si) photonic crystal devices suffer from large residual tensile strain, especially for long waveguides, because fine structures tend to crack due to large stress. By introducing spring-like tethers, des ...

In this paper, we present an improved version of microcavity light-emitting diodes, relying on the use of a low-index material, aluminum oxide. Our work addresses in particular the injection scheme required by the insulating nature of this oxide. The device we fabricated demonstrated efficiencies up to 28% in air, using only planar technology. In these structures, most of the emission is guided. We further propose to include photonic crystals to extract this guided light. The design of the photonic crystals

Summary form only given. We report the demonstration of high output power (>1 W), single frequency and ultra-short pulse operation (50 nm) by simply changing the lasing spot position on the wafer. We also demonstrate, for the first time to our knowl

The ability of using integrated photonics to scale multiple optical components on a single monolithic chip offers key advantages to create miniature light-controlling chips. Numerous scaled optical components have been already demonstrated. However, presen ...

Fast and label-free techniques to analyze viruses and bacteria are of crucial interest in biological and bio-medical applications. For this purpose, optofluidic systems based on the integration of photonic structures with microfluidic layers were shown to ...

We have studied the effect of growth interruptions on 2 monolayer thick InAs/InP strained quantum wells (QWS) grown by chemical beam epitaxy. The main feature is the formation of up to 8 monolayer thick InAs islands during As, annealing of the QW. Their formation is characterized by a two- to three-dimensional transition of the reflection high energy electron diffraction (RHEED) pattern and by multiple-line photoluminescence spectra. This interpretation of the data is confirmed by transmission electron micr

Local tuning of the optical response of GaAs-based two dimensional photonic crystals (PhCs) is reported. A selective polymer infiltration technique was developed. Scanning electron microscopy and optical measurements were used to characterize the filled Ph ...

We report on the first experimental demonstration of resonant optical trapping of dielectric particles in a two-dimensional hollow photonic crystal cavity. The cavities are implemented in an optofluidic chip consisting of a silicon-on-insulator substrate a ...

Romuald Houdré

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Si and III-nitride based photonic crystal cavities for optical trapping and non-linear optics

Impact of the residual disorder on the slow light regime in 1D and 2D photonic crystals structures

Properties of alloyed AuGeNi-contacts on GaAs/Ga/AlAs-heterostructures

Coupling length of silicon-on-insulator directional couplers probed by Fourier-space imaging

Characterization of the feature-size dependence in Ar/Cl2 chemically assisted ion beam etching of InP-based photonic crystal devices

Spectral tuning and near-field imaging of photonic crystal microcavities

Efficient second harmonic generation in a doubly resonant photonic crystal cavity based on a bound state in the continuum

Direct observation of an ac Stark splitting in semiconductor microcavities excited above the continuum onset

Artificial Band Discontinuities at GaAs Homojunctions

Strain engineering and strain measurement by spring tethers on suspended epitaxial GaN-on-Si photonic crystal devices

Toward ultrahigh-efficiency aluminum oxide microcavity light- emitting diodes: Guided mode extraction by photonic crystals

Propagation loss measurements and Fabry-Pérot mode analysis using out-of-plane light scattering in photonic crystals waveguides

Diode-pumped broadband vertical-external-cavity surface-emitting semiconductor lasers. Design and applications

Ultra-wide-band structural slow light

Gram-type differentiation of bacteria with 2D hollow photonic crystal cavities

Fourier analysis of Bloch wave propagation in photonic crystals

Effect of growth interruptions on ultra thin InAs/InP quantum grown by chemical beam epitaxy

Design, fabrication and optical characterisation of quantum cascade lasers at terahertz frequencies using photonic crystal reflectors

Local tuning of the optical response of two-dimensional photonic crystals

Self-trapping and back-action effects in hollow photonic crystal cavity optical trap