This paper is going to emphasize on the air squeeze film damping effect on micro-mechanical resonant beam in MEMS. In general, the low energy density of electrode force will cause high-voltage power supply to drive the electro- micro resonators; reducing the distance between the electrode and resonant beam can be the most efficient way to solve this problem. But bringing different exciting frequency of system and environmental pressure to the air squeeze film effect might cause it changes form similarly to the damping qualities, and this will also change the dynamic characteristics of micro resonator. The dynamic model for double clamped micro-mechanical resonant beam is proposed by using Lagrange¡¦s equation in this study. The corresponding eigenvalue problems of resonant beam are formulated and solved by employing the hypothetical mode method. Under the presumption of viscous damping model, we may obtain a damping factor which includes the parameters of size, temperature and air pressure when energy transfer model is employed to simulate the squeeze film damping effect of two immediate objects. Eventually, the damping ratio and the dynamic characteristics of resonant microbeam are derived by means of exploring the frequency response function of system. Besides, the frequency change of micro-mechanical resonant beam due to an axial force is also considered in the thesis.

A microelectromechanical systems (MEMS)-based environmental monitoring platform was presented in this dissertation. All devices were realized using thin-film piezoelectric-on-substrate (TPoS) technology, which provides a path to integrate various functionalities on a single substrate with MEMS components. TPoS resonators exhibit high quality factors (Qs) in air and are capable of low-power oscillator implementation, which further qualifies such a platform for mobile and portable systems. To validate the TPoS platform, gravimetric humidity sensing was demonstrated with thermally-corrected output by an uncoated "reference" temperature sensor. Also presented were TPoS sensors for toluene and xylene, which are pollutants of great importance for indoor and outdoor air quality as well as health screenings. Silicon dual-mode resonators and oscillators for self-temperature sensing were also explored. Dual-mode thermometry exploits the inherent frequency-temperature dependence of silicon to accurately and locally measure device temperature, forming an essential building block of highly stable oscillators and sensors. Multi-axis piezo-on-Si kinetic energy harvesting (KEH) devices with integrated frequency-upconverting transducers were also introduced. Devices were micromachined on the same substrate as TPoS resonant sensors and have an individual volume in mm3, enabling applications in wireless autonomous sensor nodes. In remote locations where continuous operation may be required, TPoS energy harvesters can provide battery replacement or recharging alternatives that do not increase overall system size.

Cette thèse étudie la conception, la fabrication et la caractérisation de micro-disques de carbure de silicium sur substrat de silicium conçus pour opérer du proche au moyen infrarouge. Nous étudions une approche simple mais efficace permettant de supprimer les modes de galerie d'ordre supérieur tout en préservant le facteur de qualité du mode fondamental. Cette suppression, utile par exemple pour la génération de peignes de fréquence se base simplement sur la sous-gravure du pilier de silicium et est aisément transposable à d'autres plateformes ou longueurs d'onde. Le premier chapitre est une introduction générale aux micro-résonateurs à modes de galerie dans lequel nous décrivons la physique extrêmement riche de ces structures. Le deuxième chapitre se concentre sur les micro-disques de SiC à proprement parler. Nous commençons par une introduction générale du matériau puis nous simulons la propagation de la lumière dans les résonateurs pour concevoir des structures innovantes. En utilisant l'indice de réfraction optique supérieur du Si à celui du SiC, nous montrons qu'il est possible de supprimer les modes radiaux d'ordre supérieur. Nous traitons ensuite brièvement des étapes de fabrication. Le troisième chapitre regroupe les expériences réalisées sur les micro-disques. Des premières caractérisations par couplage évanescent dans le proche infrarouge permettent d'identifier les modes de galerie du résonateur. Ensuite, des caractérisations sur des disques de sous-gravure inférieure mettent en évidence la suppression des modes d'ordre supérieur. Nous réalisons enfin une étude thermo-optique du matériau afin de valider son emploi à forte puissance et haute température, des régimes dans lesquels le SiC se démarque des autres matériaux d'optique intégrée. Pour terminer, nous consacrons le dernier chapitre aux perspectives pour l'optique non-linéaire et le moyen infrarouge où nous proposons une étude de l’ingénierie de la dispersion qui doit nous permettre, à l’avenir, de réaliser des sources de type peigne de fréquence. / This Ph.D. thesis studies the design, fabrication and characterization of silicon carbide micro-disks on top of silicon designed to operate from the near to the mid-IR. We study a simple but efficient approach leading to the suppression of higher order whispering gallery modes while preserving the fundamental mode's quality factor. This suppression, typically useful for frequency comb generation is simply based of the silicon pillar under etching and can be easily transferred to other material platforms and wavelengths. The first chapter is a general introduction of whispering gallery mode micro-resonator in which we describe the extremely complex and diverse physics of these structures. The second chapter is focused on SiC micro-disks themselves. We begin with a general introduction of the material to continue by simulating light propagation inside these resonators to be able to design innovative structures. Using the higher optical refractive index of silicon compared to the one of silicon carbide, we demonstrate that it is possible to suppress higher radial modes. We then briefly describe the fabrication processes. The third chapter gather the experimental studies lead on the micro-disks. First characterizations by evanescent coupling in the near infrared enable us to identify the whispering gallery modes inside the resonator. Characterization on micro-disks with smaller under-etching then enables us to demonstrate the higher suppression. We finally lead a thermo-optic study of the material to validate its compatibility to high power and high temperature regimes in which SiC stand out from other integrated optics materials. Finally, the last chapter is dedicated to non-linear optics and mid-infrared perspectives. We propose a dispersion study that, we hope, should enable the generation of Kerr frequency combs sources in a near future.

The G-center has recently been identified as the first deterministic single-photon punctual emitter isolated in silicon. This discovery is of great interest for largescale quantum technologies, due to the abilities of silicon in terms of integration and scalability. However, the spontaneous emission rate of the G-center still needs to be controlled in order to engineer a useful Single-Photon Source. This could be achieved by incorporating a single G-center in resonant microcavities to benefit from the Purcell effect. As a first step in this direction, we have studied in this project micro-cavities containing an ensemble of G-centers, more precisely Si micro-disks and micro-rings on oxide, with several objectives: the evaluation of the quality factor of micro-cavities containing G-centers, the demonstration of an optical activity of G-centers after the processing of the silicon micro-structures, and the evaluation of their potential as gain medium for integrated microlasers on SOI. The observation of bright photoluminescence from G-centers and of resonant cavity modes with Q’s in the few thousands range confirms the compatibility of G-centers with standard silicon processing steps, and is encouraging for future quantum optics experiments on isolated G centers in micro-cavities. Our results also tend to show that gain may be available in the material, but residual absorption still needs to be decreased to achieve lasing. / G-center har nyligen identifierats som den första determinitiska ponctual enfoton källen isolerad i kisel. Denna upptäckt är av stort intresse för kvantteknologier p.g.a. kisels förmåga gällande integration och skalbarhet. G-centers spontana rekombinationshastighet behöver dock kontrolleras för att skapa en användbar enfoton källa. Det kan göras genom Purcell-effekten i en optisk resonator. Som ett första steg har vi studerat mikroresonatorer som innehåller G-center i det presenterade projektet, med flera mål: utvärdering av kvalitetsfaktor för mikroresonatorer som innehåller G-center, demonstration av optisk aktivitet av G-center efter tillverkning av kiselmikrostrukturer, och utvärdering av deras potential för integrerade mikrolaser på SOI. Observation av stark fotoluminescens av G-center och resonatormoder med stor-Q bekräftar kompatibilitet mellan G-center och vanliga steg för bearbetning av kisel, och är uppmuntrande för framtida Kvantum Optik experimenter med isolerade G-center i mikroresonatorer. Resultaten visar att ljusförstärkning troligtvis börjar, men absorption av andra defekter måste minskas för att uppnå laserregim.

The first objective of this Dissertation is to present a methodology to calculate analytically the mode shapes and corresponding natural frequencies and determine critical buckling loads of mechanically coupled microbeam resonators with a focus on micromechanical filters. The second objective is to adopt a nonlinear approach to build a reduced-order model and obtain closed-form expressions for the response of the filter to a primary resonance. The third objective is to investigate the feasibility of employing subharmonic excitation to build bandpass filters consisting of either two sets of two beams coupled mechanically or two sets of clamped-clamped beams. Throughout this Dissertation, we treat filters as distributed-parameter systems. In the first part of the Dissertation, we demonstrate the methodology by considering a mechanical filter composed of two beams coupled by a weak beam. We solve a boundary-value problem (BVP) composed of five equations and twenty boundary conditions for the natural frequencies and mode shapes. We reduce the problem to a set of three linear homogeneous algebraic equations for three constants and the frequencies in order to obtain a deeper insight into the relation between the design parameters and the performance metrics. In an approach similar to the vibration problem, we solve the buckling problem to study the effect of the residual stress on the static stability of the structure. To achieve the second objective, we develop a reduced-order model for the filter by writing the Lagrangian and applying the Galerkin procedure using its analytically calculated linear global mode shapes as basis functions. The resulting model accounts for the geometric and electric nonlinearities and the coupling between them. Using the method of multiple scales, we obtain closed-form expressions for the deflection and the electric current in the case of one-to-one internal and primary resonances. The closed-form solution shows that there are three possible operating ranges, depending on the DC voltage. For low DC voltages, the effective nonlinearity is positive and the filter behavior is hardening, whereas for large DC voltages, the effective nonlinearity is negative and the filter behavior is softening. We found that, when mismatched DC voltages are applied to the primary resonators, the first mode is localized in the softer resonator and the second mode is localized in the stiffer resonator. We note that the excitation amplitude can be increased without worrying about the appearance of multivaluedness when operating the filter in the near-linear range. The upper bound in this case is the occurrence of the dynamic pull-in instability. In the softening and hardening operating ranges, the adverse effects of the multi-valued response, such as hysteresis and jumps, limit the range of the input signal. To achieve the third objective, we propose a filtration technique based on subharmonic resonance excitation to attain bandpass filters with ideal stopband rejection and sharp rolloff. The filtration mechanism depends on tuning two oscillators such that one operates in the softening range and the other operates in the hardening range. Hardware and logic schemes are necessary to realize the proposed filter. We derive a reduced-order model using a methodology similar to that used in the primary excitation case, but with all necessary changes to account for the subharmonic resonance of order one-half. We observe that some manipulations are essential for a structure of two beams coupled by a weak spring to be suitable for filtration. To avoid these complications, we use a pair of single clamped-clamped beams to achieve our goal. Using a model derived by attacking directly the distributed-parameters problem, we suggest design guidelines to select beams that are potential candidates for building a bandpass filter. We demonstrate the proposed mechanism using an example. / Ph. D.

Ce travail porte sur l'étude de propriétés optiques des fluides à échelle micrométrique. A cet effet, nous avons conçu, réalisé et étudié différents types de micro-résonateurs optofluidiques, sous forme de laboratoires sur puce. Notre analyse est fondée sur la modélisation analytique et numérique, ainsi que sur des mesures expérimentales menées sur des micro-cavités optiques; nous utilisons l'une d'entre elles pour des applications de réfractométrie de fluides homogènes et de fluides complexes ainsi que pour la localisation par piégeage optique de microparticules solides. Nous nous sommes d'abord concentrés sur l'étude d'une nouvelle forme de micro-cavité Fabry-Pérot basée sur des miroirs courbes entre lesquels est inséré un tube capillaire permettant la circulation d'une solution liquide. Les résultats expérimentaux ont démontré la capacité de ce dispositif à être utilisé comme réfractomètre avec un seuil de détection de 1,9 × 10-4 RIU pour des liquides homogènes. De plus, pour un liquide contenant des particules solides, la capacité de contrôler la position des microparticules, par des effets de piégeage optique ou de liaison optique, a été démontrée avec succès. Dans un second temps, un résonateur optique est formé simplement à partir d'une goutte de liquide disposée sur une surface super-hydrophobe. La forme quasi-sphérique résultante est propice à des modes de galerie. Il est démontré que, jusqu'à des tailles de gouttelettes millimétriques, la technique de couplage en espace libre est toujours en mesure d'accéder à ces modes à très faible queue évanescente d'interaction, contrairement à ce qu'indiquait jusqu'ici la littérature. De tels résonateurs optofluidiques à gouttelette devraient trouver leur application notamment comme capteur d'environnement de l'air ambiant ou encore comme incubateur de micro-organismes vivants pouvant être suivis par voie optique / This work focuses on the study of optical properties of fluids at the micrometer scale. To this end, we designed, implemented and studied different types of optofluidic micro- resonators in the Lab-on-Chip format. Our analysis is based on analytical and numerical modeling, as well as experimental measurements conducted on optical microcavities; we use one of them for refractometry applications on homogeneous fluids and on complex fluids, as well as for the localization of solid microparticles by optical trapping. We first focused on the study of a new form of Fabry-Perot micro-cavity based on curved mirrors between which a capillary tube is inserted for injecting a fluidic solution. Experimental results demonstrated the ability of this device to be used as a refractometer with a detection limit of 1.9 × 10-4 RIU for homogeneous liquids. Furthermore, for liquid containing solid particles, the ability to control the microparticles position either by optical trapping or optical binding effects has been successfully demonstrated. In a second step, an optical resonator is simply formed from a liquid droplet placed on top of a superhydrophobe surface. The resulting quasi-spherical shape supports resonant whispering gallery modes. It is shown that, up to millimeter size droplets, the proposed technique of free-space coupling of light is still able to access these modes with very low evanescent tail interaction, contrary to what was indicated in the literature so far. Such optofluidic droplet resonators are expected to find their applications for environmental air quality monitoring, as well as for incubator of living micro-organisms that can be monitored optically