Local thermal resonance control of GaInP photonic crystal membrane cavities using ambient gas cooling

We perform spatially dependent tuning of a GaInP photonic crystal cavity using a continuous wave violet laser. Local tuning is obtained by laser heating of the photonic crystal membrane. The cavity resonance shift is measured for different pump positions and for two ambient gases: helium and nitrogen. We find that the width of the temperature profile induced in the membrane depends strongly on the thermal conductivity of the ambient gas. For He gas a narrow spatial width of the temperature profile of 2.8 um is predicted and verified in experiment.Comment: 4 pages, 5 figure

Strongly coupled slow-light polaritons in one-dimensional disordered localized states

Cavity quantum electrodynamics advances the coherent control of a single quantum emitter with a quantized radiation field mode, typically piecewise engineered for the highest finesse and confinement in the cavity field. This enables the possibility of strong coupling for chip-scale quantum processing, but till now is limited to few research groups that can achieve the precision and deterministic requirements for these polariton states. Here we observe for the first time coherent polariton states of strong coupled single quantum dot excitons in inherently disordered one-dimensional localized modes in slow-light photonic crystals. Large vacuum Rabi splittings up to 311 {\mu}eV are observed, one of the largest avoided crossings in the solid-state. Our tight-binding models with quantum impurities detail these strong localized polaritons, spanning different disorder strengths, complementary to model-extracted pure dephasing and incoherent pumping rates. Such disorder-induced slow-light polaritons provide a platform towards coherent control, collective interactions, and quantum information processing.Comment: 17 pages, 5 figures and supplementary informatio

Transistors à nanofils de silicium top-down. Application à la détection biologique.

Ce travail de thèse a porté sur la réalisation d'un capteur d'espèces biologiques en solution à partir de réseaux organisés de nanofils de silicium opérant sur le mode d'un transistor à effet de champ à "grille biologique". Cette nouvelle génération de biocapteurs vise à être intégrée dans des systèmes de détection ultrasensibles et compacts destinés à des applications médicales et militaires. Nous proposons la réalisation des transistors à nanofils de silicium suivant une approche dite "top-down". Cette méthode, qui consiste à graver les nanofils dans une couche mince de silicium, permet un contrôle précis de leur positionnement, contrairement à l'approche "bottom-up", qui utilise des nanofils obtenus par croissance CVD. Ceci permet l'obtention de transistors aux caractéristiques électriques reproductibles et facilite leur intégration. La première partie de nos travaux a ainsi concerné le design et la fabrication de transistors à nanofils de silicium suivant une approche top-down. Ce travail de développement technologique a permis la réalisation de composants que nous avons caractérisés à sec puis adaptés à un fonctionnement en milieu liquide. La seconde partie de nos travaux a porté sur la réalisation de mesures en solution. La validation du fonctionnement de notre transistor en mode capteur a été démontrée par le suivi de variations de pH. Notre étude a ensuite eu pour objet la mise en valeur de l'ensemble des paramètres influençant les performances du capteur (choix de la tension de grille, de la force ionique, influence de la microfluidique, ...), la compréhension de ces facteurs étant indispensable à la réalisation de mesures biologiques fiables.This work focuses on biological sensors based on an array of silicon nanowires operating as a field-effect transistor with a "biological gate". This new kind of biosensors is devoted to be integrated into ultrasensitive and compact detection systems for medical and security applications. We propose to fabricate silicon nanowire transistors in a "top-down" approach. This method, which consists in etching nanowires in a thin film, allows to precisely control nanowire position, contrary to the bottom-up approach, which uses CVD-grown nanowires. This enhances the reproducibility of the electrical characteristics of the transistors and eases their integration into a fluidic environment. The first part of our work focuses on the design and fabrication of top-down silicon nanowire transistors. These technological efforts lead us to characterize fabricated transistors in ambient air before integrating them into a liquid environment. The second part presents the results of real-time electrical measurements performed in solution. We demonstrate that our transistor can work as a sensor by monitoring pH variations. Then our study highlights the parameters affecting the sensor sensitivity (gate voltage value, ionic strength, microfluidics, ...), considering that the understanding of these factors is essential to perform reliable monitoring of biological interactions.PALAISEAU-Polytechnique (914772301) / SudocSudocFranceF

A Highly Linear All Optical Gate Based on Coupled Photonic Crystal Cavities

International audienceA photonic crystal molecule is used as an all-optical gate to perform sampling of microwave signals. We demonstrate a very linear operation over a 50dB still with a 1.2mW power consumption

Exciton-Photon Coupling of InAs Quantum Dot in GaAs Photonic Crystal Mode-Gap Nanocavities

We demonstrate single quantum dot coupled to photonic crystal mode-gap cavities with high Q/V ratio. Polarization and temperature dependent photoluminescence are examined. Predominating polarization is observed for quantum dot coupled to cavity mode

Strong Coupling between Single Quantum Dot and Localized Mode in Photonic Crystal Waveguide

Strong coupling between single QD and PhC localized mode is observed and theoretical modeling is performed. The results show the great potential of slow-light waveguide for enhanced light-matter interaction and quantum information processing

Broadband tunable hybrid photonic crystal-nanowire light emitter

We integrate about 100 single cadmium selenide semiconductor nanowires in silicon nitride photonic crystal cavities in a single processing run. Room temperature measurements reveal a single and narrow emission linewidth, corresponding to a Q-factor as large as 5000. By varying the structural parameters of the photonic crystal, the peak wavelength is changed, thereby covering the entire emission spectral range of the active material. A very large spectral range could be covered by heterogeneous integration of different active materials.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore)Accepted versio