Single-photon sources are essential building blocks in quantum photonic networks, where quantum-mechanical properties of photons are utilised to achieve quantum technologies such as quantum cryptography and quantum computing. In this thesis, a single-photon source driven by a surface acoustic wave (SAW) is developed and characterised. This single-photon source is based on a SAW-driven lateral n-i-p junction in a GaAs quantum-well structure. On this device, the lateral n-i-p junction is formed by gate-induced electrons and holes in two adjacent regions. The SAW potential minima create dynamic quantum dots in a 1D channel between these two regions, and are able to transport single electrons to the region of holes along the channel. Single-photon emission can therefore be generated as these electrons consecutively recombine with holes. After characterisation and optimisation in four batches of devices, clear SAW-driven charge transport and the corresponding electroluminescence (EL) can be observed on an optimised SAW-driven n-i-p junction. Time-resolved measurements have been carried out to study the dynamics of SAW-driven electrons. Time-resolved EL signals indicate that a packet of electrons is transported to the region of holes in each SAW minimum. In addition, the carrier lifetime of SAW-driven electrons in the region of holes is shown to be $\sim 100$ ps, which is much shorter than the SAW period of $860$ ps. Hence, it is promising to observe single-photon emission in the optimised device. In order to test single-photon emission, a Hanbury Brown-Twiss experimental setup has been employed to record an autocorrelation histogram of the SAW-driven EL signal at the single-electron regime. Suppression of autocorrelation coincidences at time delay $\Delta t = 0$ is evidence of photon antibunching. By fitting theoretical functions describing the SAW-driven EL signal, it is found that the second-order correlation function shows $g^{(2)}(0) = 0.39 \pm 0.05$, which is lower than the common criterion for a single-photon source $g^{(2)}(0) < 0.5$. Moreover, theoretical calculation and simulation suggest that, if a constant background signal can be filtered out, $\sim 80 \%$ of the SAW-driven EL is single-photon emission.

First, one of the purposes of this thesis is to estimate the complete crosstalk effects including the package and the pads on the surface acoustic wave (SAW) substrate. A new approach based on finite-difference time-domain (FDTD) with equivalent current source method is applied. Two kinds of patterns of one-port SAW resonators with the same package structure and inter-digital transducer (IDT) design are studied. Verification with the measurement results shows that our method is able to obtain good agreement and be used to observe the influence from the SAW pattern. Second, the equivalent current source method is extended to model the excitation of human-body¡¦s electrostatic discharge (ESD) situations. The efficiencies of sacrificial electrodes are also discussed. Finally, a novel sacrificial electrode with fractal to protect SAW devices from ESD break is proposed. Comparing with traditional electrode, the simulation results show that fractal can improve the protective efficiency greatly. Finally, a novel analysis model that can be used to analyze and optimize the impedance of an RFID transponder integrated circuit (IC) which uses backscatter encoding based on simultaneously maintaining the BER of the reader and maximizing the received power of the transponder IC is proposed. The analysis method utilizes mapping from signal constellation of the backscattered signal to the Smith chart to relate the two parameters. Given the system specification and characteristics of the reader and transponder antennas, the optimum impedances of transponder IC for binary communication system can be easily designed by using this model.

Particle separation is of great interest to many biological and biomedical applications. Flow-based methods have been used to sort particles and cells. However, the main challenge with flow based particle separation systems is the need for a sheath flow for successful operation. Existence of the sheath liquid dilutes the analyte, necessitates precise flow control between sample and sheath flow, requires a complicated design to create sheath flow and separation efficiency depends on the sheath liquid composition. In addition, current gold standard active separation techniques are only capable of separation based on particle size; hence, separation cannot be achieved for same-size particles with different densities. In this dissertation, a sheathless acoustic-based microfluidic platform using surface acoustic wave for not only size-dependent but also density-dependent particle separation has been investigated. In this platform, two different functions were incorporated within a single microfluidic channel with varying the number of pressure node and position. The first function was to align particles on the center of the microfluidic channel without adding any external sheath flow. The second function was to separate particles according to their size or density. Two different size-pairs of polystyrene particles with different diameters (3 µm and 10 µm for general size-resolution, 3 µm and 5 µm for higher size-resolution) were successfully separated. Also, the separation of two 10 µm diameter, different-density particle streams (polystyrene: 1.05 g/cm3, melamine: 1.71 g/cm3) was successfully demonstrated. The effects of the input power, the flow rate, and particle concentration on the separation efficiency were investigated. A range of high separation efficiencies with 94.8-100 % for size-based separation and 87.2 - 98.9 % for density-based separation were accomplished. In this dissertation, an acoustic-based microfluidic platform using dual acoustic streaming for active mixing has also been investigated. The rapid and high efficiency mixing of a fluorescent dye solution and deionized water in a microfluidic channel was demonstrated with single acoustic excitation by one interdigital transducer (IDT) as well as dual excitation by two IDTs. The mixing efficiencies were investigated as a function of applied voltage and flow rates. The results indicate that with the same operation parameters, the mixing efficiency with dual-IDT design increased to 96.7 % from 69.8 % achievable with the traditional single-IDT design. The effect of aperture length of the IDT on mixing efficiency was also investigated. Additionally, the effects of the polydimethylsiloxane (PDMS) channel wall thickness on the insertion loss and the particle migration to the pressure node due to acoustic radiation forces induced by SAW have been investigated. The results indicate that as the PDMS channel wall thickness decreased, the SAW insertion loss is reduced as well as the velocity of the particle migration due to acoustic forces increased significantly. As an example, reducing the side wall thickness of the PDMS channel from 8 mm to 2 mm in the design results in 31.2 % decrease in the insertion loss at the resonant frequency of 13.3 MHz and 186 % increase the particle migration velocity at the resonant frequency of 13.3 MHz with input power of 27 dBm. Lastly, a novel acoustic-based method of manipulating the particles using phase-shift has been proposed and demonstrated. The location of the pressure node was adjusted simply by modulating the relative phase difference (phase-shift) between two IDTs. As a result, polystyrene particles of 5 µm diameter trapped in the pressure node were manipulated laterally across the microfluidic channel. The lateral displacements of the particles from -72.5 µm to 73.1 µm along the x-direction were accomplished by varying the phase-shift with a range of -180° to 180°. The relationship between the particle displacement and the phase-shift of SAW was obtained experimentally and shown to agree with theoretical prediction of the particle position.

Bond rupture is an experimental methodology that is used to augment a conventional mass balance biosensor. A good point-of-care biosensor is fast, reliable, simple, cost-effective, and detects low concentrations of the target analyte. Biosensor development is a multidisciplinary field and bond rupture testing is of technical interest to many groups. The Bond rupture methodology endows a mass probe with the ability to discern bond strength. The recognition of specific bonds by mass loading is separated from erroneous non-specific binding by a probe of the force between the analyte and the transducer. Bond rupture is achieved by acoustic excitation of the point of attachment. The force is incremented gradually until rupture occurs. The advancement of bond rupture biosensors beyond the lab requires improved understanding of the mechanisms of bond rupture by base excitation, the transducers, and the supporting hardware. Bond rupture has traditionally been used in conjunction with the Quartz Crystal Microbalance (QCM). There exists, however, a variety of sensors and transducers to which the bond rupture methodology could be applied. The time, cost and experience required for comprehensive investigation of all avenues is prohibitive. To further the development of bond rupture characteristic experiments are designed and carried out on the QCM platform. Numerical simulations are constructed which model the current bond rupture approach. This work is limited to the simulation of bond rupture by base excitation. From the results of the experimental investigation a number of improvements to the bond rupture technique are proposed. Improvements are tested by simulation and the Surface Acoustic Wave (SAW) device is selected to advance the bond rupture craft. A prototype SAW bond rupture device is designed. The prototype device is manufactured and tested, confirming the principle of SAW bond rupture. Future work is required to progress the SAW bond rupture methodology before possible integration with other sensor systems. Because of this work, and the evaluation of the SAW bond rupture prototype, much is learned about the advancement of SAW device bond rupture.

Les ultrasons laser font partie des techniques expérimentales d'inspection en développement pour des problématiques de contrôle non destructif toujours plus exigeantes. Ces méthodes sans contact permettent dans notre cas de générer et détecter des ondes de surface se propageant sur des distances de quelques dizaines de microns.L'objectif de cette thèse est de mettre au point et tester une méthode ultrasons lasers pour l'étude d'échantillons d'aciers polycristallins. En effet ces matériaux à la base d'un ensemble de pièces manufacturées sont composés d'une multitudes de cristaux anisotropes de tailles et d'orientations variables. Parmi les paramètres physiques d'intérêt l'évaluation des constantes élastiques ainsi que la détermination de texturations sont des facteurs essentiels dans toute application CND et leur simulation numérique. Dans un premier temps, les variations de vitesses de propagation dues à l'anisotropie et aux l'orientation différentes des cristaux sont mesurées grâce au montage expérimental en surface d'échantillons d'acier austénitique. Les résultats sont exploités sous la forme de distributions statistiques de vitesses de propagation et un protocole d'inversion est proposé pour l'évaluation des constantes élastiques. Dans une seconde partie, un échantillon d'acier moulé présentant de larges macrograins est analysé pour la mise en évidence de sous-structures au sein d'un milieu biphasique.Finalement un échantillon de soudure possédant une texturation typique avec grains allongés est étudié et la présence d'une orientation préférentielle est soulignée. / Laser ultrasonics are among the most interesting experimental technics to answer the need of industrials in NDT applications. These non contact methods allow to generate and detect elastic surface wave propagating on typical distances of several tens of microns.The main objective of this thesis is to test laser ultrasonics methods for polycristalline steel study. These materials are composed of several anisotropic crystals with differents sizes and orientations. Among the essential parameters to describe such material, the determination of elastic parameters and texturations are key to good understanting and for the modelisation of material in NDT studies.In a first part, velocities variations due to elastic anisotropy and crystalline orientation of grains is assessed by measuring surface acoustic wave velocity. The experimental results are used in the form of statistical distribution of velocity combined with a numerical model to evaluate elastic parameters.Stainless casted steel is a complex material presenting large biphasic grains. They are here studied to show the presence of sub-structures.Finally, a weld sample presenting typical structuration of ellongated grains is studied to show the presence of preferential orientation.

Polypyrol (PPy) je heterocyklický vodivý polymer s chemickou strukturou založenou na existenci systému konjugovaných elektronů mezi střídajícími se jednoduchými a dvojnými vazbami. Díky svým vynikajícím vlastnostem jako je dobrá elektrická vodivost, relativně vysoká stabilita prostředí a zároveň i jednoduchost a variabilita metod jeho přípravy, přilákal tento polymer pozornost mnoha vědců z různých vědních disciplín. Cílem výzkumu v této dizertační práci byla studie senzorického chování PPy. Za tímto účelem byla ověřena účinnost nanostruktur PPy při detekci vybraných „vysoce důležitých molekul plynů“ včetně acetonu, amoniaku, etanolu, etylenu a toluenu. V této práci byl připraven PPy ve formě nanotyčinek (NRs) pomocí elektrochemické syntézy a také ve formě nanočástic (NPs) chemickou cestou. Dále byly připraveny modifikované PPy struktury, a to funkcionalizací PPy NPs katalytickými částicemi zlata (Au), stříbra (Ag) a teluridu kademnatého (CdTe). Pro charakterizaci morfologie, složení a struktury připravených materiálů bylo použito několik komplementárních analytických (mikroskopických i spektroskopických) technik. Navíc byly využity techniky jako Ramanova a rentgenová fotoelektronová spektroskopie (XPS) pro in-situ test detekce plynů, které potvrdily potenciál připraveného materiálu, tedy PPy NRs i PPy NPs, pro využití v senzorech plynů. Za účelem výroby senzoru plynů byl připravený PPy materiál integrován do dvou typů převodníkových platforem: chemorezistivní a na bázi povrchové akustické vlny v tzv. Love módu (L-SAW). Test detekce plynů pro chemorezistivní senzory s PPy NRs ukázal pouze zanedbatelnou odpověď těchto senzorů pro oxid dusičitý a amoniak z důvodu jejich komplikované architektury. Změření odzevy tvou typú chemorezistivních senzorů-nemodifikovaného i modifikovaného PPy NPs nebylo možné z dúvodu extrémně vysoké odporu v řádu G. Nicméně multivodivé L-SAW senzory založené na holých PPy NPs či PPy NPs modifikovaných Au či Ag NPs a nebo CdTe kvantovými tečkami (QDs) vykazovaly odezvu pro nízké koncentrace všech testovaných velmi důležitých molekul plynů při pokojové teplotě (RT). Obecně měly L-SAW senzory s modifikovanou citlivou vrstvou vyšší citlivost než senzory s nemodifikovanou PPy citlivou vrstvou. Účinnost L-SAW senzoru primárně závisí na pracovní frekvenci a na výběru citlivé vrstvy v aktivní oblasti senzoru. Z otestovaných typů vrstev senzoru vuči jednotlivým plynům, modifikovaná PPy NPs s Ag NPs i Au NPs se javí jako nejlepší varianta pro detekci acetonu. Připravené L-SAW senzory na bázi PPy jsou jednoduchá a cenově přijatelná zařízení s vylepšenými detekčními vlastnostmi jako je vysoká senzitivita a nízký limit detekce (LOD), což je řadí mezi potenciální kandidáty v budoucích systémech pro kontrolu kvality vzduchu, potravin a rovněž pro diagnostiku nemocí z dechu.

The theoretical part of this thesis deals with principles and characteristics of the surface acoustic wave filter. It explained the principle of magnetostriction and piezoelectric effect, which uses a filter. In the practical part in the program Comsol Multiphysics are made three simple models of SAW filter. Some modes are founded and are compared to previously known results. In the next phase of project is further studied using the parametric analysis. In the last phase of project is applied global optimization PSO at admittance characteristic from simple 2D structure. The results are compared with the commercially produced devices.

Currently, there is no equipment to measure the real-time fit of EHMR or N-95masks which are used in harsh environments. Improper fit of these EHMRs or N-95 masks exposes the personnel to hazardous environments. Surface acoustic wave (SAW) sensors have been around for few decades and are being used in various applications. In this work, real-time PM2.5 detection using passive wireless SAW sensors is presented. The design of meander antenna at 433MHz for wireless interrogation of SAW sensor using HFSS and ADS is also presented in this thesis. This works also includes the design of YZ-lithium niobate SAW sensor including COMSOL simulation.

SAW based sensors can offer wireless, passive operation in numerous environments and various device embodiments are employed for retrieval of the sensed data information. Single sensor systems can typically use a single carrier frequency and a simple device embodiment, since tagging is not required. In a multi-sensor environment, it is necessary to both identify the sensor and retrieve the sensed information. This dissertation presents the concept of orthogonal frequency coding (OFC) for applications to SAW sensor technology. OFC offers all advantages inherent to spread spectrum communications including enhanced processing gain and lower interrogation power spectral density (PSD). It is shown that the time ambiguity in the OFC compressed pulse is significantly reduced as compared with a single frequency tag having the same code length and additional coding can be added using a pseudo-noise (PN) sequence. The OFC approach is general and should be applicable to many differing SAW sensors for temperature, pressure, liquid, gases, etc. Device embodiments are shown and a potential transceiver is described. Measured device results are presented and compared with COM model predictions to demonstrate performance. Devices are then used in computer simulations of the proposed transceiver design and the results of an OFC sensor system are discussed.

Surface acoustic wave (SAW) technology has been in use for well over one century. In the last few decades, due to its low cost and high performance, this technology has been widely adopted in modern wireless communication systems, to build filtering devices at radio frequency (RF). SAW filters and duplexers can be virtually found inside every mobile handset. SAW devices are traditionally recognized as passive devices with high linear signal processing behavior. However, recent deployments of third generation (3G) and fourth generation (4G) mobile networks require the handsets to handle an increasing number of frequency bands with more complex modulation /demodulation schemes and higher data rate for more subscribers. These requirements directly demand more stringent linearity specifications on the front end devices, including the SAW duplexers. In the past, SAW duplexer design was based on empirically obtained design rules to meet the linearity specifications. Lack of predictability and an understanding of the root cause of the nonlinearity have limited the potential applications of SAW duplexers. Therefore, research on the nonlinearity characterization and an accurate modeling of SAW nonlinearity for mobile device applications are very much needed. The Ph.D. work presented here primarily focuses on developing a general nonlinear model for SAW resonators/duplexers. Their nonlinear characteristics were investigated by measuring the harmonic and intermodulation distortions of resonators. A nonlinear Mason model is developed and the characterization results are integrated into SAW duplexer design flows to help to simulate the nonlinear effects accurately and improve the linearity performance of the products. iv In this dissertation, first, a novel nonlinear Mason equivalent circuit model including a third order nonlinear coefficient in the wave propagation is presented. Next, the nonlinear distortions of SAW resonators are analyzed by measuring large-signal harmonic and intermodulation spurious emission on resonators using a wafer probe station. The influence of the setups on the measurement reliability and reproducibility is discussed. Further, the nonlinear Mason model is validated by comparing its simulation results with harmonic and intermodulation measurements on SAW resonators and a WCDMA Band 5 duplexer. The Mason model developed and presented here is the first and only nonlinear physical model for SAW devices based on the equivalent circuit approach. By using this new model, good simulation measurement agreements are obtained on both harmonic and intermodulation distortions for SAW resonators and duplexers. These outcomes demonstrate the validity of the research on both the characterization and modeling of SAW devices. The result obtained confirms that the assumption of the representation of the 3 rd order nonlinearity in the propagation by a single coefficient is valid