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Microelectromechanical systems (MEMS) combine electrical components with mechanical systems on a micro scale. MEMS devices involve miniature micron-size mechanical moving structures manufactured using semiconductor-based fabrication. Deep reactive ion etching (DRIE) of silicon is widely used in MEMS device fabrication. Etching often involves creating narrow but deep trenches. It is one of the most popular fabrication techniques due to its flexibility between anisotropic and isotropic etching and high selectivity. However, the DRIE-based fabrication technique often has significant challenges, mainly from manufacturing process variations that lead to microstructure variations and induce various fabrication tolerances. However, these multiple tolerances, such as slanted etched profiles, DRIE scallops, and undercuts, can be avoided if the process focuses on a subset of features. This thesis presents numerical and analytical modeling techniques to understand the performance effect of slanted etched profiles, thickness, and undercut effects on frequency shifts in a reference model of micro-resonators, The analytical modeling result of the reference model was 726.86 Hz, while numerical analysis with 310,000 number of meshes reveals 772 Hz. The result of numerical calculation shows that increasing the angle of etch profile from 89° to 91° at the thickness of 60 μm, reduces the frequency response from 875.37 Hz to 650.22 Hz. Also, the result shows that for the case of 90° etch profile, the thickness of the structural layer has no influence on the frequency response. For other angles of etch profile, the thickness has an influence on the frequency. The undercut has a significant effect on the frequency response. For example, when the thickness of the structural layer is 60μm and angle of etch profile is 90°, changing the undercut from 0 μm to 4 μm resulted in the frequency changing from 770.33 Hz to 26.168 Hz.

Thermal and mechanical relaxation times play essential roles in the thermal quality factor Q - f a c t o r of the micro-resonators, where controls the energy damping through the coupling of thermal and mechanical behavior. In this work, we developed an analytical mathematical model that assumed a pre-stress in a two-temperature micro-viscothermoelastic resonator of silicon to modify the thermal and mechanical relaxation times and thus increase the thermal quality factor. The impacts of length-scale and pre-stress on the thermal quality factor have been discussed. The present model predicts that significant enhancement in terms of thermal quality factors is enabled by tuning the static-pre-stress, the thermal and mechanical relaxation times parameters. The isothermal value of frequency and the two-temperature parameter have impact effects on the thermal quality factor of the micro-resonators.

Biosensors are devices used to detect the presence of biomolecules in a sensing field, which can be a liquid or a gas. The use of integrated optics allows to exploit various interactions of biomolecules with propagated light in compact and easily realizable guiding structures, such as micro-resonators. In this thesis, we use porous silicon in the fabrication of our optical transducers for biosensors. It is a biocompatible material with a large specific surface on which molecules can be grafted. It also allows to exploit the surface detection of biomolecules directly in the volume of the material because of its porous nature. The material must first get a biofunctionalization process to allow the infiltration of molecules in the pores that compose it. Using a photolithography process, micro-resonators are fabricated to be used as transducers for the surface detection of BSA. The presence of the protein in the detection field will induce a quantifiable change in the properties of the transducers related to the concentration of BSA. A sensitivity of more than 1000 nm/RIU could be obtained and is better than the state of the art. The realization of a hybrid structure based on porous silicon and polymers is studied. The advantage of the coupled use of porous silicon and polymers is to allow the reduction of propagation losses while improving the performances of this type of biosensor.; Les biocapteurs sont des dispositifs servant à détecter la présence de biomolécules dans un milieu de détection, qui peut être un liquide ou un gaz. L’utilisation de l’optique intégrée permet d’exploiter diverses interactions des biomolécules avec la lumière propagée dans des structures guidantes compactes et facilement réalisables, comme le sont les micro-résonateurs. Dans cette thèse, nous utilisons du silicium poreux dans la fabrication de nos transducteurs optiques composant les biocapteurs. Il s’agit d’un matériau biocompatible présentant une surface spécifique importante sur laquelle peuvent être greffées des molécules. Il permet aussi d’exploiter la détection surfacique de biomolécules directement dans le volume du matériau de par sa nature poreuse. Le matériau a au préalable besoin de subir un procédé de biofonctionnalisation pour permettre l’infiltration de molécules dans les pores qui le compose. En utilisant un procédé de photolithographie, des micro-résonateurs sont fabriqués pour être utilisés comme transducteurs pour la détection surfacique de BSA. La présence de la protéine dans le milieu de détection va induire une modification quantifiable des propriétés des transducteurs et liée à la concentration de la BSA. Une sensibilité de plus de 1000 nm/UIR a pu être obtenue et se révèle meilleure que l’état de l’art. La réalisation d’une structure hybride à base de silicium poreux et de polymères est étudiée. L’avantage de l’utilisation couplée du silicium poreux et des polymères est de permettre la réduction des pertes de propagation tout en améliorant les performances de ce type de biocapteur.

Integrated photonic micro-resonators have numerous applications in the range of detection and fine metrology. The works presented in this thesis aim at studying and list their use for the diagnosis and the tracking of dynamic soft matter processes such as measurements of sedimentation speed, detections of phase transitions related to products from galenic pharmacology, food industry, cosmetics… The theoretical and mathematical minimum description related to the operating principle of microresonators is presented. It first deals with definitions of eigenvalues associated to a guiding structure (effective propagation constant associated with the optical mode), then on the notion of evanescent coupling in waves physics. The generic transfer function of the global resonant photonic structure is then computed, giving rise to the fundamental spectral attributes of signals. The fabrication process in clean room of such structures and the compete mounting of the measurements and optical signals treatment platformare t hen developed. This platform has been inforced to study different dynamic processes associated to soft matter which will be tracked in real time by the resonant lught probes. These phenomena are : the mecansim of brutal condensation vapor, the evaporation of a sessile water droplet and the differential loss of mass measurements, the measures of the speed of sedimentation of nano-particles, and the tracking of phase transitions ; this last application concerns respectively the gel/fluid transition of sphingomyelin and on a morphological phase transition of a compound of fatty acids. Finally, mathematical developments are realized in order to work out a formulation interating all the geometric variations of the structure, and thus describing a displacement on the dispersion curves during the said processes.; Les micro-résonateurs photoniques intégrés ont de nombreuses applications dans le domaine de la détection et de la métrologie fine. Les travaux présentés au cours de cette thèse ont pour objet d’étudier et de répertorier leurs utilisations pour le diagnostic et le suivi de processus dynamiques de la matière molle comme les mesures de vitesses de sédimentation, les détections de transitions de phases propres aux produits de pharmacologie galénique, de l’agro-alimentaire, de la cosmétique… Le minimum théorique mathématique relatif au principe de fonctionnement des micro-résonateurs est présenté. Il porte tout d’abord sur les définitions des valeurs propres en électromagnétisme associés aux structures guidantes (constante de propagation effective associée au mode propre optique), puis sur la notion de couplage évanescent en physique des ondes. La fonction de transfert générique de la structure photonique globale résonnante est ensuite calculée, donnant lieu aux attributs spectraux fondamentaux des signaux. Les procédés de fabrication en salle blanche de telles structures puis le montage complet de la plateforme de mesures et traitement des signaux optiques sont ensuite développés. Cette plateforme a été mise en oeuvre afin d'étudier différents processus dynamiques associés à la matière molle qui seront suivis en temps réels par les sondes de lumière résonnante. Ces phénomènes sont : les mécanismes de condensation brusque de vapeur, l'évaporation d'une goutte d'eau sessile et la mesure différentielle de perte de masse, les mesures de vitesse de sédimentation, puis le suivi des transitions de phase ; cette dernière application porte respectivement sur une transition gel/fluide de la sphingomyéline et sur une transition morphologique d'un composé d'acide gras. Enfin, des développements mathématiques sont réalisés dans le but de construire une formulation intégrant l’ensemble des variations géométriques de la structure et décrivant donc un déplacement sur les courbes de dispersion lors des dits processus.

We have investigated the effect of sudden water condensation processes and the behavior of its condensed water prior evaporation, with an integrated resonant photonic structure and dynamic tracking of its transduced signal. The aim of this analysis is to develop a water condensation lab-on-chip sensor, with the possibility of data treatment with an embedded system. Integrated photonic micro-resonator (MR) devices have been designed and fabricated with polymer UV210 by means of Deep-UV photolithography. Thanks to this technique, we have achieved racetrack shaped micro-resonators coupled to suited access waveguides. We have assessed such MRs with different geometrical characteristics while changing, respectively, the coupling length (LC), the radius of curvature (R) and the width (w) of the guides. The chosen values for the set of parameters LC-R-w (in μm) are 5-5-3 and 10-10-3. The laser source used with the injection bench is a Gaussian broadband laser (λcentral = 790 nm, FWHM = 40 nm) allowing us to visualize several resonances at the same time in order to multiplex the relevant measurements. The transduced spectrum is then acquired with an optical spectrum analyzer (OSA) linked to a computer with Labview and MATLAB software recording and processing data in real time. Then, relevant characteristics to be tracked are the Free Spectral Range (FSR) and the transmitted energy; these quantities can be linked to the physical characteristics of the structure considering both the effective refractive index and the absorption coefficient. The experimental setup also includes various movies with a top-view imaging camera of the chip (MRs) recording the soft matter process steps, so as to correlate the changes in the transduced spectrum and the behavior of the condensed water mechanisms (condensation, coalescence and evaporation). Then, the chip is fitted with a temperature controller, so as to carry out measurements at different temperatures: 20, 24 and 28 °C.

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., 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.; 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.

International audience; The present paper describes biophotonic sensors realized by way of inexpensive processes. As hybrid silica/polymer resonators, they are suited to detect biological molecules in gel/fluid phase transition at infinitesimal concentrations (sphingomyelin lipids). The photonic structure is made of specific amplified deep UV210 photoresist-polymer waveguides coupled by a sub-wavelength gap with racetrack microresonators allowing a minimal dependence in temperature. Then, temperature dependent wavelength shifts characterizing the optical resonances of the device have been evaluated, highlighting a quite low thermal feature of the sensor advantageous for relevant applications. With an appropriate vesicle lipid deposition process, specific in biology, together with an apt experimental bio-thermo-photonic protocol, the dynamic evolution of the sphingomyelin lipid phase transition has been assessed. The ability to detect their gel/fluid transition phase and melting temperature has been demonstrated with a mass product factor value 1.4×10 7 lower than that of classical methods. The equilibrium regimes of the resonators and the scattered part of the light are clearly highlighted as markedly modified by the dynamic of the sphingomyelin during its own phase transition.

International audience; An overview of targeted current research on integrated photonics based on the new deep-UV210 organic material is given [1-5]. We report on the interest in this new material and properties coupled to deep-ultraviolet (DUV) lithography processes towards the realization and optical characterization of sundry photonics structures. Such structures include sub-wavelength waveguides, pedestal and tapers waveguides until serial of optical micro-resonators shaped as disk, ring, stadium and racetrack for sensors devoted to glucose detection. The overall design, fabrication and optical characterization of single and multiple resonant micro-structures patterned on the UV210 polymer and shaped by adequate deep-UV lithography procedures will be presented. Various families of ring and racetrack forms are investigated with different geometrical dimensions linked to the micro-resonators and the specific taper-waveguides and gaps allowing the optimized coupling. Well defined photonic structures families in the sub-micrometer range obtained by this deep UV-light process are clearly confirmed through scanning electron microscopy. In order to evaluate and quantify the efficiency of the sub-micrometer coupling, the recirculation of the light and the quality of the optical resonance aspects, a global study including top view intensity imaging, spectral measurements and Fast Fourier Transform analysis is performed for all these devices based on single and multiple family resonators. The experimental TE-mode resonance transmissions reveal a complete agreement with the period of the theoretically expected resonances. Moreover, the large thermo-optic coefficient and the detection principle based on the interaction of the evanescent field with different glucose concentrations demonstrate that this sensor displays high sensitivity on detection properties. Glucose homogeneous sensing capability will be also presented. Different concentrations of glucose solutions result in a red shift of the resonant wavelengths with a linear sensitivity close to 280 pm/(mg/ml).

Diamond is a highly desirable material for state-of-the-art micro-electromechanical (MEMS) devices, radio-frequency filters and mass sensors, due to its extreme properties and robustness. However, the fabrication/integration of diamond structures into Si-based components remain costly and complex. In this work, a lithography-free, low-cost method is introduced to fabricate diamond-based micro-resonators: a modified home/office desktop inkjet printer is used to locally deposit nanodiamond ink as ∅50–60 µm spots, which are grown into ≈1 µm thick nanocrystalline diamond film disks by chemical vapor deposition, and suspended by reactive ion etching. The frequency response of the fabricated structures is analyzed by laser interferometry, showing resonance frequencies in the range of ≈9–30 MHz, with Q-factors exceeding 104, and (f0 × Q) figure of merit up to ≈2.5 × 1011 Hz in vacuum. Analysis in controlled atmospheres shows a clear dependence of the Q-factors on gas pressure up until 1 atm, with Q ∝ 1/P. When applied as mass sensors, the inkjet-printed diamond resonators yield mass responsivities up to 981 Hz fg−1 after Au deposition, and ultrahigh mass resolution up to 278 ± 48 zg, thus outperforming many similar devices produced by traditional top-down, lithography-based techniques. In summary, this work demonstrates the fabrication of functional high-performance diamond-based micro-sensors by direct inkjet printing.

International audience; We report and demonstrate the feasibility of a laterally coupled racetrack microresonator based on UV210 photoresist to act as a thermal and glucose sensor. The large thermo-optic coefficient and the detection principle based on the interaction of the evanescent field with different glucose concentrations demonstrate that this sensor displays high sensitivity on detection properties. Deep-UV lithography procedures allow us to develop a laterally coupled microresonator with submicrometer patterns. The thermo-optic response of the racetrack microresonator is interrogated by using a NiCr alloy tip positioned on the top of the device. Temperatures ranging between 19 and 33ºC yield a red shift of the resonant wavelength with a linear sensitivity of 220 pm ºC-1. Additionally, the thermal tunability is successively demonstrated by covering the resonator with DI water. A blue shift of the resonant wavelength is obtained with a linear sensitivity of 200 pm ºC-1. The resonance optical properties under this top cladding conditions lead a Q-factor of 4000 with a finesse of 5.7. Glucose homogeneous sensing capability is also experimentally demonstrated. Different concentrations of glucose solutions result in a red shift of the resonant wavelengths with a linear sensitivity of 280 pm/(mg/ml). Finally, these results validate the laterally coupled racetrack microresonator as an operative photonic component for integrated optical devices such as optical filters applied on telecommunication, or transducer components devoted to assess biochemical interactions.

International audience; An overview of targeted current research on integrated photonics based on the new deep-UV210 organic material is given. We report on the interest in this new material and properties coupled to deep-ultraviolet (DUV) lithography processes towards the realization and optical characterization of sundry photonics structures. Such structures include sub-wavelength waveguides, pedestal and tapers waveguides until serial of optical micro-resonators (MRs) shaped as disk, ring, stadium and racetrack.

International audience; Research on sensors has experienced a noticeable development over the last decades especially in label free optical biosensors. However, compact sensors without markers for rapid, reliable and inexpensive detection of various substances induces a significant research of new technological solutions. The context of this work is the development of a sensor based on easily integrated and inexpensive micro-resonator (MR) component in integrated optics, highly sensitive and selective mainly in the areas of health and food. In this work, we take advantage of our previous studies on filters based on micro-resonators (MR) to experiment a new couple of polymers in the objective to use MR as a sensing function. MRs have been fabricated by processing SU8 polymer as core and PMATRIFE polymer as cladding layer of the waveguide. The refractive index contrast reaches 0.16 @ 1550 nm. Sub-micronic ring waveguides gaps from 0.5 to 1 µm have been successfully achieved with UV (i-line) photolithography. This work confirms our forecasts, published earlier, about the resolution that can be achieved. First results show a good extinction coefficient of ~17 dB, a quality factor around 104 and a finesse of 12. These results are in concordance with the theoretical study and they allow us to validate our technology with this couple of polymers. Work is going on with others lower cladding materials that will be used to further increase refractive index contrast for sensing applications.

The revolution in mobile Information-Communication Technology (ICT) devices evident today is based on three principal trends: (i) constant miniaturization for increased portability; (ii) exponential increase in the volume of data stored and transmitted; and (iii) reduced power consumption for extended autonomy and Green-ICT applications. Currently, ICT devices are based on semiconductor technology, which has been experiencing a tremendous increase in performance and density, following a continuous miniaturization trend known as Moore’s law. Nevertheless, semiconductor technology faces severe limitations on the time horizon 2019 and beyond [1]. Indeed, as the gate length of semiconductor transistors shrinks below the design rule of 20 nm, leakage currents considerably reduce their performance, thereby calling for a new generation of alternative approaches: the so-called “More than Moore” technologies. One such approach having so far demonstrated great promise focuses on spin-transfer devices, which exploit the spin degree of freedom of the conduction electrons in order to manipulate their electronic properties. A variety of applications are being explored in this context, including non-volatile memory and wireless communication, with some being close to commercialization [2]. An even more recent research area: spincaloritronics, which aims at investigating new phenomena that can enable inherently generated Joule heating to be functionalized in microelectronic circuit design, bringing about a new generation of Green-ICT devices. Indeed, it has been theoretically predicted and demonstrated that temperature gradients can induce spin-currents and spin-accumulation in ferromagnets (known as the spin-Seebeck effect) [3], as well as tunneling between two magnetic layers separated by an insulator (magneto-Seebeck effect) [3], spin-injection from a ferromagnet to a semiconductor (spin Seebeck tunneling) [4] and so on. It has also been suggested that spin currents generated by temperature gradients in magnetic tunnel junctions can induce spin-transfer torques large enough to cause switching [3], although experimental evidence remains elusive. This proposal focuses on fundamental research aimed at experimentally demonstrating that thermal gradients can generate spin-transfer torques in MgO-based magnetic tunnel junctions (MTJs). Specifically, we propose a novel approach which will allow us to provide proof-of-concept even if the magnitude of the torques that can be realistically achieved is considerably lower than predicted theoretically. References: [1] http://www.jsap.or.jp/english/images/academic_roadmap/arm_e_11.pdf. [2] http://www.everspin.com/. [3] G.E.W. Bauer, E. Saitoh and B.J. van Wees, Nature Mater. 11, 391 (2012) and references therein. [4] R. Jansen, Nature Mater. 11, 400 (2012) and references therein.

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.

Paper reports recent advances in optical nanomaterials, planar microcavity, and spherical microresonators. Bottom-up fabrication and optical assessment of Er3+-activated SiO2-HfO2 waveguide glass ceramic is presented. Concerning confined structures, fabrication by radio-frequency sputtering (RFS) technique of an Er3+-activated microcavity with a quality factor of 171 using oxide-based dielectric materials is demonstrated and fabrication and spectroscopic assessment of Er 3+-activated silica microspheres is presented.

Within the past few years, the field of Electron Spin Resonance has become an important tool in physical, chemical and biological research. However, in many cases its usefulness is limited by the sensitivity of the experimental setup. A typical example is the study of very limited sample quantities such as tissues, cellular structures, single cells, and also thin films in microelectronic technologies. For such volume limited samples, the typical dimensions and/or spatial variations of the properties of interest range between 1 µm and 1 mm. Present X-band ESR spectrometers are optimized for samples having a volume between (1 mm)3 and (1 cm)3, and achieve a spin sensitivity of about 1010 spins/G√Hz at room temperature. Setting up new high sensitivity ESR spectrometers would overcome this limitation and open the way to numerous new applications. The goal of the present work is to study and develop innovative devices in combination with modern continuous ESR detection method to achieve a spin sensitivity of 109 spins/G√Hz or better at room temperature, specifically conceived for samples having dimensions and/or spatial variations in the range between 1 µm and 1 mm. We mainly focus our investigation efforts on the design of ESR-setups based on miniaturized sensitive devices. Miniaturization concerns size reduction of the sensitive volume where the sample will be placed, i.e., the region in which the microwave magnetic field is generated. In this work two approaches will be investigated. Inductive transverse magnetization detection by means of planar structures based on coplanar waveguide (CPW) resonator design. Single turn coils and straight trace constrictions with different dimensions are designed as sensitive regions to accommodate the appropriate sample size. These constrictions are built with open-ended half-wavelength and shorted (or shunted) quarter-wavelength lines related to the working resonance frequency. Appropriate microfabrication technologies are also developed based on two substrate candidates, SU-8 and RO4003C, with Aluminum and Copper metals, respectively. Performance of the RO4003C based-resonators proves to be better than that for the SU-8 based ones in terms of the conversion factor describing the efficiency of conversion of microwave power to magnetic field strength. The analysis we have performed shows that the dielectric losses induced in the RO4003C substrate are much lower than those induced in SU-8 one. This improves the Q-factor by almost a factor 10. Since the conversion factor varies as Q1/2, this, in turn, enhances the power conversion efficiency by almost a factor 3. Detection efficiency is also improved by almost the same factor. As a result, a spin sensitivity of about 109 spins/G√Hz is achieved at room temperature for sensitive volumes of about (100 µm)3. This result is one order of magnitude better than that of existing X-band spectrometers. Longitudinal magnetization detection using a Hall-based probe. A resonant cavity and a CPW-resonator are used to generate the microwave field. Rather than a large rectangular cavity and its disperse field lines, the CPW-resonator offers a smaller structure. Its compact geometry is suitable for small volumes, since it concentrates the microwave magnetic field precisely at the sample. This approach eliminates several experimental difficulties of cavity-employed ESR spectroscopy and better controls the electromagnetic environment of the sample, avoiding the properties of the cavity resonator which suffer from thermal drifts and background instabilities. In addition, thanks to their greater sensitivity, the CPW-resonators require much less microwave power than waveguide cavities, to generate the same microwave magnetic field. The achieved spin sensitivity is about 109 spins/G√Hz at room temperature for sensitive volumes of about (10 µm)3 . This result is, once more, one order of magnitude better than that of conventional X-band spectrometers. The obtained results confirm the effectiveness of the combination of the CPW-resonators for small sample analysis for practical enhancement of the ESR spectrometer sensitivity at X-band frequencies. Furthermore, a key aspect of the present work is the ability to go further in miniaturization: the concept of coplanar waveguide structures is very simple and easy to implement for the required ESR measurements without too much additional design complexity and change to fabrication procedures. This should be very promising, and especially highly motivating to achieve in-vivo ESR measurements inside living organism and to perform high spatial resolution ESR-imaging.