This thesis describes the fabrication and characterization of waveguides in the nonlinear, Raman-active optical crystal potassium gadolinium tungstate (KGW). Ion implantation and femtosecond laser writing techniques are used for the first time to fabricate waveguides in this material. The light ion implanted waveguides using hydrogen ions showed unexpected refractive index increases in the damage regions of approximately 0.3% of the nominal refractive index values for three of the four polarization orientations, with only the highest refractive index polarization exhibiting a refractive index decrease of approximately 0.2%. Waveguides fabricated using high-energy carbon, oxygen and fluorine ion irradiations resulted in strongly confining waveguides with wide amorphous damage regions. Carbon ion irradiation of KGW showed the most promise, with sharp step-like waveguides with a maximum refractive index change of delta-n=0.2 with excellent preservation of the Raman properties in the waveguide core. Microreflectivity measurements on the carbon ion irradiated sample revealed unexpected intermittent refractive index changes in the core region, a feature not detected using standard characterization techniques found in the literature. The oxygen ion irradiation of KGW also generated strongly confining waveguides with a maximum refractive index change of delta-n=0.17, however the Raman performance was shown to be reduced to less than 50% in the waveguide cores. Fluorine ion irradiations of KGW resulted in amorphous regions fabricated in the surface regions, offering promise for masking techniques for creating two-dimensional structures. The waveguides written using femtosecond laser writing processes were used to write buried channel waveguides using compressive stresses to form the waveguide. These waveguides exhibited low-losses down to to 2.0 dB/cm in the telecommunications spectrum, with high coupling efficiency to SMF fiber, and excellent Raman properties in the waveguide core. These channel waveguides also successfully showed SRS generation into the 1.8-1.9 \mu m infrared region using a high power picosecond pump source in the telecommunications band. The use of the microreflectivity and micro-Raman spectroscopy measurement techniques were demonstrated to be valuable characterization tools for each of the fabrication methods.

This thesis describes the fabrication and characterization of waveguides in the nonlinear, Raman-active optical crystal potassium gadolinium tungstate (KGW). Ion implantation and femtosecond laser writing techniques are used for the first time to fabricate waveguides in this material. The light ion implanted waveguides using hydrogen ions showed unexpected refractive index increases in the damage regions of approximately 0.3% of the nominal refractive index values for three of the four polarization orientations, with only the highest refractive index polarization exhibiting a refractive index decrease of approximately 0.2%. Waveguides fabricated using high-energy carbon, oxygen and fluorine ion irradiations resulted in strongly confining waveguides with wide amorphous damage regions. Carbon ion irradiation of KGW showed the most promise, with sharp step-like waveguides with a maximum refractive index change of delta-n=0.2 with excellent preservation of the Raman properties in the waveguide core. Microreflectivity measurements on the carbon ion irradiated sample revealed unexpected intermittent refractive index changes in the core region, a feature not detected using standard characterization techniques found in the literature. The oxygen ion irradiation of KGW also generated strongly confining waveguides with a maximum refractive index change of delta-n=0.17, however the Raman performance was shown to be reduced to less than 50% in the waveguide cores. Fluorine ion irradiations of KGW resulted in amorphous regions fabricated in the surface regions, offering promise for masking techniques for creating two-dimensional structures. The waveguides written using femtosecond laser writing processes were used to write buried channel waveguides using compressive stresses to form the waveguide. These waveguides exhibited low-losses down to to 2.0 dB/cm in the telecommunications spectrum, with high coupling efficiency to SMF fiber, and excellent Raman properties in the waveguide core. These channel waveguides also successfully showed SRS generation into the 1.8-1.9 \mu m infrared region using a high power picosecond pump source in the telecommunications band. The use of the microreflectivity and micro-Raman spectroscopy measurement techniques were demonstrated to be valuable characterization tools for each of the fabrication methods.

Ce travail de thèse s’inscrit dans les efforts actuellement réalisés, pour améliorer l’efficacité des pinces optiques conventionnelles qui permettent de manipuler sans contact des objets de quelques dizaines de nanomètres à quelques dizaines de micromètres avec une extrême précision et trouvent de nombreuses applications en biophysique et sciences de colloïdes.L’objectif de cette thèse a été d’explorer une nouvelle approche pour la réalisation de Nanopinces Optiques. Elle s’appuie sur l’utilisation de cavités à cristaux photoniques à modes de Bloch lents. Ces cavités peuvent être efficacement et facilement excitées par un faisceau Gaussien à incidence normale. Contrairement aux pinces optiques conventionnelles, des objectifs à faibles ouvertures numériques peuvent être utilisés. Les performances attendues en termes de piégeage vont bien au-delà de limitations imposées par la limite de diffraction pour les pinces conventionnelles. Ce travail démontre expérimentalement l’efficacité de l’approche. Cette thèse comporte deux parties principales. Dans un premier temps, il a fallu monter un banc expérimental pour mener nos études. Nous avons construit un banc optique, interfacé les instruments, et développé des applications logicielles pour analyser les données. Deux éléments importants ont présidé à sa construction : - Le développement d’un système optique permettant d’exciter les nanostructures photoniques - la conception d’un système d’imagerie pour suivre les nanoparticules. La seconde partie de ce travail a porté sur la mise en évidence du piégeage optique à l’aide de nanostructure à base de cristaux photonique. Nous avons d’abord montré que même des cavités possédant des coefficients de qualités modérés (quelques centaines) permettait d’obtenir des pièges optiques dont l’efficacité est d’un ordre de grandeur supérieur à celui de pinces conventionnels. Fort de ce résultat, nous avons exploré un nouveau type de cavité à cristaux photoniques s’appuyant sur une approche originale : des structures bi-périodiques. Nous avons montré qu’à l’aide de cette approche des facteurs de qualités de l’ordre de plusieurs milliers étaient facilement atteignable. A l’aide de ces nouvelles structures, nous sommes arrivés aux résultats le plus important de ce travail : le piégeage de nanoparticules de 250nm de rayon avec une puissance optique incidente de l’ordre du milliwatt. Une analyse fine du mouvement de la nanoparticule, nous a permis de trouver la signature du mode de Bloch lent. / This thesis aims at improving the efficiency of conventional optical tweezers (cOT). They allow to manipulate objects with dimension from a few tens of nanometer to a few tens of micrometers with a high accuracy and without contact. This has numerous applications in biophysics and colloidal science. This thesis investigates a new approach for optical nanotweezers. It uses a photonic crystal (PC) cavity which generates a slow Bloch mode. This cavity can be effectively and easily excited with a Gaussian beam at the normal incidence. Contrarily to cOT, objective with a small numerical aperture can be used. The expected performances in terms of trapping go well beyond the diffraction limit of cOT. This work demonstrates experimentally the efficacy of approach. This thesis is divided in two main sections. First, we had to set up an experimental bench to carry out to our study. We built the optical bench interface instruments and develop programs to analyze the data. Two essential elements have been considered: - The development of the optical system allowing the excitation of the photonics nanostructure. - The design an imaging system to track nanoparticles. Second, we have focus on the demonstration of the optical trapping. We started by with a low Q factor (few hundred) cavity. Trapping efficiency of an order of magnitude higher than cOT has been demonstrated. Then, we have explored a new king of PC cavity based on double period structure. We show that thanks to this approach high Q factor of several thousand are easily reached. With this structure, we managed to trap 250nm polystyrene beads, with an optical power of the order of a milliwatt. A deep analysis of the nanoparticle trajectories allowed us to find a slow Bloch mode signature.