La détection précoce de biomarqueurs de maladies telles que le cancer représente un intérêt majeur dans le processus de traitement. En effet, un diagnostic avancé augmente considérablement les chances de réussite du traitement. En pratique, cela nécessite des outils permettant de détecter rapidement d'infimes quantités de composants biologiques (anticorps, protéines, ADN...) au sein d'échantillons réels tels que du sang ou du sérum.Ces dernières années, les avancées et progrès technologiques en matière de micro et nanofabrication ont permis le développement des Micro et Nano Systèmes Electro-Mécaniques (M/NEMS) dans de nombreux domaines d'application et notamment celui de la détection de masse. Ainsi, des nano-capteurs de masse atteignant des résolutions de l'ordre du yoctogram ($10^{-24}g$), soit la masse d'un seul proton ont été développés. De telles résolutions permettraient d'utiliser ces capteurs à des fins de biodétection. Ces résultats ont cependant été obtenus sous vide ce qui est incompatible avec le monde biologique. Immergés en liquide, les performances des M/NEMS traditionnels sont drastiquement réduites notamment à cause de l'amortissement du au fluide. Un nouveau type de résonateur à base de microdisques optomécaniques résonants a ainsi vu le jour démontrant un fort potentiel pour la détection en milieu liquide. Là où les méthodes classiques de transduction électriques des M/NEMS éprouvent des difficultés en liquide, l'exceptionnelle sensibilité de la transduction optomécanique permet de surmonter ce problème.Dans ce cadre, ces travaux de thèse visent à développer un biocapteur à base de microdisques optomécaniques résonants en silicium pour la détection biologique en milieu liquide. Le design, la fabrication ainsi que la caractérisation complète de ces capteurs est décrite. Enfin, une preuve de concept de détection de virus T5 à une concentration de quelques pM à l'aide de ces microdisques est également présentée. / Early detection of disease's biomarkers such as cancer represents a major interest in the treatment process. Indeed, a diagnosis at an early stage considerably increases the chance of the treatment to be successful. Practically, tools allowing the rapid detection of tiny amount of biological compounds (antibodies, proteins, DNA...) in real samples such as blood or serum are needed.Over the last years, the advances and progresses of micro and nanofabrication techniques have allowed the development of Micro-Nano Electro Mechanical Systems (M/NEMS) in various fields of application including mass sensing. Thus, nano mass sensors reaching resolution down to the yoctogram level, the equivalent of a single proton have been demonstrated. Such resolution limit would theoretically allow these sensors to be used as potential biosensors. These results were nonetheless obtained in vacuum conditions which is incompatible with the biological world. Immersed in fluid, the performance of traditional M/NEMS are drastically degraded mostly due to the large viscous damping. A new type of object in the form of optomechanical microdisk resonators have recently emerged, demonstrating a huge potential for sensing in liquid. While M/NEMS classical electrical or optical transduction methods become very challenging in liquid, the astonishing sensitivity of the optomechanical transduction overcomes this major issue.In this context, this thesis work aims at developing a biosensor based on silicon optomechanical microdisk resonators for biosensing in liquid. Design, fabrication along with the complete characterization of theses devices is described. Eventually, a proof-of-concept of T5 virus detection at the pM level using these microdisks is presented.

Cavity quantum electrodynamics provide a platform to form a quantum network which connects individual quantum bits (qubits) via photon. Optical cavity, a device which traps photons in a confined volume can enhance the interaction between photons and the qubits serves as fundamental building block for a quantum network. Nitrogen vacancy (NV) centers in diamond has emerged as one of the leading solid-state qubits because of its long spin coherence time and single photon emission properties at room temperature. Diamond optical micro-cavities are highly sought after for coupling with NV centers. Fabrication of optical cavities from nano-crystalline diamond film has been demonstrated previously. The quality factor (Q) of such devices was limited by the material properties of the nano-crystalline diamond film. Fabrication of single-crystal diamond photonic cavities is challenging because there is no trivial way to form thin diamond film with optical isolation. In this thesis, we describe an approach to fabricate high quality single-crystal diamond optical cavities for coupling to NV centers in diamond. ingle-crystal diamond membranes were generated using an ion-slicing method. Whispering gallery modes were observed for the first time from microdisk cavities made from such material. However, the cavity Q (∼ 500) was limited by the ion damage created during processing. By using an homo-epitaxial overgrowth method, a high quality diamond film can be grown on the ion damaged membranes. Microdisk cavities with Q ∼ 3,000 were fabricated on these improved materials. Diamond membranes with a delta-doped layer of NV can be made using a slow overgrowth process which demonstrate the position and density of NV centers can be controlled in these membranes. Photonic crystal cavities with Q ∼ 4,000 were fabricated from the delta-doped membranes with cavity resonance near the zero phonon line of NV centers. Different color centers can also be introduced during the overgrowth process, and optical coupling of an ensemble of silicon vacancy centers is demonstrated by coupling to a diamond microdisk cavity. We believe the techniques developed in this thesis could contribute to building of a quantum photonic network using diamond as a platform. / Engineering and Applied Sciences