Les Sciences de l’Information et de la Communication ayant nouvellement investi les services en ligne et en particulier le domaine du e learning- largement occupé par les sciences de l’éducation, les sciences cognitives, la psychosociologie ou encore l’informatique- notre objectif est d’aborder cette question selon trois figures de pensée rencontrées dans la recherche en enseignement à distance : la substance, la relation et le mouvement. Après avoir envisagé les médiations à partir de la fonction de la substance qui s’intéresse aux caractéristiques des acteurs/actants par rapport au dispositif ou à la nature de celui-ci, on a porté notre attention sur la relation, car c’est depuis ce « entre » que chaque sujet en lui-même va se construire. Il en va ainsi du modèle de communication, lui-même intermédiaire, un « entre ». Dans cette perspective, la communication médiatisée procède d’abord de la qualité de la relation, des situations comme celles qui se nouent entre les registres, comme la dimension technique et les composantes médiationnelles du e-learning. Enfin, avec la figure du mouvement, on s’est affranchi de la figure de la substance et de la relation en les dépassant, pour penser en termes de dynamique et de processus, soit dans notre cas aux modalités de l’agencement homme-machine ou homme-homme. Le modèle qui en résulte semble ne reposer qu’en partie sur la proposition technologique, voire pédagogique, mais sur des formes persistantes de médiation agissant dans le dispositif. La spatialisation des compétences à distance ramène le curseur autour d’un axe médiationnel dans un domaine que l’on pourrait désormais appeler apprentissage intégré («integrated learning ») et qui renvoie à l’intégration de toutes les dimensions d’un objet de connaissance. / The Communication and Information sciences have lately invested on-line services and in particular the field of the e-learning, largely occupied by the sciences of education, cognitive sciences, social psychology or data processing. Our objective is to tackle this question according to the three figures of thought in research in elearning: the substance, the relation and the movement. After having considered the mediations starting from the function of the substance which is interested in the characteristics of the actors/agents compared to the process or nature of this one, we have focused our attention on the relation, because it is from this “between” that each subject in itself will be built. It goes from there thus from the model of communication, in itself intermediary. In this point of view, the mediatized communication proceeds first of all from the quality of the relation, of the situations as those which are tied between the registers, such as technical dimension and the mediational components of the e-learning. Finally, with the figure of movement, we freed ourselves from the figure of substance and relation by exceeding them, by thinking in terms of dynamics and of process. Thus in our case thinking according to the process man-machine or man-man, which calls for an “engineering”. The model which is implied seems to rest only partly on the technological, even pedagogical proposal, but also on persistent forms of mediation acting as a process. The spatialization of e-learning skills brings back the cursor around a mediational axis in a field which we could from now on call “integrated learning” and which sends back to the integration of all dimensions of an object of knowledge.

Nowadays, the increasing concern for environmental analysis and food quality control, as well as medical needs such as fast diagnosis in case of emergency events, leads to a growing need for new generations of chemical and biological sensors. These devices should have high sensitivity and reliability, perform specific detection of molecules and enable multiple parallel sensing, while being cheap, portable, fast and easy to use. Thus, a general trend tends towards bio-chemical sensors which are on-chip integrated, label-free, and compatible with standard micro-technologies. Photonic dielectric devices based on porous silicon and metallic nanostructures based on plasmon resonances are good candidates to fulfill the above requirements. Porous silicon is a biocompatible material, with a huge specific surface providing a sensitivity enhancement by several orders of magnitude compared to bulk materials; furthermore, its refractive index and thickness can be easily tuned, enabling for the realization of a large variety of photonic designs. Metallic nanostructures provide high confinement and strong field enhancement in sub-wavelength regions, leading to high sensitivities; combined with fluorescence or other sensing mechanisms such as Raman or IR spectroscopy, they have already demonstrated increased sensing potential. The realization of a hybrid device combining both elements would be highly interesting, since it could yield the advantages of both elements, and the photonic structure could shape the plasmonic resonance to develop ultrasensitive devices with narrow resonance linewidth and increased sensing depth. In this context, we realized and studied a novel hybrid photonic / plasmonic device exploiting the coupling between the surface plasmon resonance of a bowtie nano - antenna (NAs) array and the photonic modes of porous silicon (PSi) interferometer. We designed and fabricated a NAs array with resonance wavelength ~ 1.3μm on a homogeneous PSi interferometer. A thin spacing silica layer with controllable density protects the pores of PSi layer and provides a smooth surface for the fabrication of NAs. The coupling mechanisms of two elements - NA array and interferometer, are studied with 2 models, which are interferometer approach and resonator approach. The interferometer approach is focused on studying the influence of NAs array as a homogeneous layer on the fringes shift of the interferometer. For resonator approach, the coupled mode theory is applied. With these models, strong coupling between both elements are discovered: splitting. In the case of viii smaller environment variation, the hybrid device gains 5-10 fold sensitivity enhancement vs. 2 elements alone. The controllable SiO2 layer allows us to sense the index variation within PSi interferometer. This opens a route towards double parallel sensing. The development of the theoretical models under different environment is ongoing, which is expected to utilize the strong coupling for the sensing. A further investigation of the sensing potential of the hybrid device would be expected. And the 2 elements constituting the hybrid structure - the interferometer and the NA array - could be modified in order to enlarge the study to a wider family of devices with greater properties and performances. This work was performed within the framework of the program "Groups of Five Ecoles Centrales" between China Scholarship Council (CSC) and Lyon Institute of Nanotechnologies (INL, CNRS UMR 5270). The project has been supported by the Nanolyon technology platform at INL.

Aujourd'hui, la préoccupation croissante pour l'analyse environnementale et le contrôle de la qualité des aliments, ainsi que les besoins médicaux tels que le diagnostic rapide en cas de situations d'urgence, entraîne un besoin croissant de nouvelles générations de capteurs chimiques et biologiques. Ces dispositifs doivent avoir une haute sensibilité et fiabilité, ils doivent permettre une détection spécifique de molécules et une détection parallèle de différentes molécules, tout en étant bas coût, portables, rapides et faciles à utiliser. Ainsi, une tendance générale se porte sur les capteurs biochimiques intégrés sur puce, sans marqueur, et compatibles avec les procédés standard des micro-technologies. Les dispositifs diélectriques photoniques à base de silicium poreux et les nanostructures métalliques à résonances plasmoniques sont de bons candidats pour répondre aux exigences ci-dessus. Le silicium poreux est un matériau biocompatible, avec une énorme surface spécifique entrainant un gain de la sensibilité de plusieurs ordres de grandeur par rapport aux matériaux massifs ; en outre, son indice de réfraction et son épaisseur peuvent être facilement ajustés, permettant la réalisation d'une grande variété de dispositifs photoniques. Les nanostructures métalliques offrent un fort confinement et une forte amplification du champ électromagnétique dans des régions sub-longueur d'onde, ce qui conduit à des sensibilités élevées ; combinées avec d’autres mécanismes de détection comme la fluorescence, le Raman ou la spectroscopie IR, elles ont déjà démontré un gain important du potentiel pour la détection. La réalisation d'un dispositif hybride combinant ces deux éléments est très intéressant, car il peut offrir les avantages des deux éléments ; la structure photonique pourrait aussi façonner la résonance plasmonique pour le développement de dispositifs ultrasensibles à largeur de raie de résonance étroite tout en ayant une profondeur de détection accrue. Dans ce contexte, l'objectif de cette thèse est d'explorer les défis de cette solution en considérant la conception, la réalisation, la caractérisation et le potentiel de dispositifs hybrides photoniques/plasmoniques qui exploitent le couplage entre la résonance plasmonique de surface localisée d'un réseau d'antennes papillon et les modes photoniques d'un interféromètre en silicium poreux. / Nowadays, the increasing concern for environmental analysis and food quality control, as well as medical needs such as fast diagnosis in case of emergency events, leads to a growing need for new generations of chemical and biological sensors. These devices should have high sensitivity and reliability, perform specific detection of molecules and enable multiple parallel sensing, while being cheap, portable, fast and easy to use. Thus, a general trend tends towards bio-chemical sensors which are on-chip integrated, label-free, and compatible with standard micro-technologies. Photonic dielectric devices based on porous silicon and metallic nanostructures based on plasmon resonances are good candidates to fulfill the above requirements. Porous silicon is a biocompatible material, with a huge specific surface providing a sensitivity enhancement by several orders of magnitude compared to bulk materials; furthermore, its refractive index and thickness can be easily tuned, enabling for the realization of a large variety of photonic designs. Metallic nanostructures provide high confinement and strong field enhancement in sub-wavelength regions, leading to high sensitivities; combined with fluorescence or other sensing mechanisms such as Raman or IR spectroscopy, they have already demonstrated increased sensing potential. The realization of a hybrid device combining both elements would be highly interesting, since it could yield the advantages of both elements, and the photonic structure could shape the plasmonic resonance to develop ultrasensitive devices with narrow resonance linewidth and increased sensing depth. In this context, we realized and studied a novel hybrid photonic / plasmonic device exploiting the coupling between the surface plasmon resonance of a bowtie nano - antenna (NAs) array and the photonic modes of porous silicon (PSi) interferometer. We designed and fabricated a NAs array with resonance wavelength ~ 1.3μm on a homogeneous PSi interferometer. A thin spacing silica layer with controllable density protects the pores of PSi layer and provides a smooth surface for the fabrication of NAs. The coupling mechanisms of two elements - NA array and interferometer, are studied with 2 models, which are interferometer approach and resonator approach. The interferometer approach is focused on studying the influence of NAs array as a homogeneous layer on the fringes shift of the interferometer. For resonator approach, the coupled mode theory is applied. With these models, strong coupling between both elements are discovered: splitting. In the case of viii smaller environment variation, the hybrid device gains 5-10 fold sensitivity enhancement vs. 2 elements alone. The controllable SiO2 layer allows us to sense the index variation within PSi interferometer. This opens a route towards double parallel sensing. The development of the theoretical models under different environment is ongoing, which is expected to utilize the strong coupling for the sensing. A further investigation of the sensing potential of the hybrid device would be expected. And the 2 elements constituting the hybrid structure – the interferometer and the NA array – could be modified in order to enlarge the study to a wider family of devices with greater properties and performances. This work was performed within the framework of the program “Groups of Five Ecoles Centrales” between China Scholarship Council (CSC) and Lyon Institute of Nanotechnologies (INL, CNRS UMR 5270). The project has been supported by the Nanolyon technology platform at INL.