This thesis presents a novel method to fabricate metallic nanostructures on whispering gallery mode (WGM) cavity surfaces. The unique properties of WGM cavities have shown their promising future in both fundamental research and engineering applications. High sensitivity biosensors are one of the most important applications. Thanks to their ultra high quality factor (Q) and small optical mode volume, the resonant frequency shift of a single nanoparticle binding becomes detectable. The basic principles of a WGM cavity and its coupling mechanism with an optical coupler are discussed in detail. From the WGM sensing principle, people have demonstrated the positive contributions of the surface plasmon to the sensitivity. Furthermore, we implement the localized surface plasmon resonance (LSPR) on the cavity surface by depositing metallic dots. We use the focused ion beam (FIB) to directly deposit metallic nanodots on the spherical cavity surface for the first time. The quality factor of the cavity with metallic dots is above 10^7 in both air and water, which is more than one order larger than other published results. Also, the new method is much more controllable and repeatable than previous methods. It reveals a new fabrication method for potential ultra sensitive sensors based on WGM cavities. In addition, we offer a new mode solver for the toroidal WGM cavity. The microtoroid is a better platform for further investigation of WGM sensing than the microsphere. By expanding cavity modes to a set of normal fiber modes, we formulate the new mode solver based on simple physical principles. The simulation results of the radiative quality factor based on the new mode solver are presented as well. / Graduate

<p> A quantum particle moving in a periodic potential, with periodicity d, when acted by an external constant force F undergoes the dynamical phenomenon of Bloch-Zener oscillations (BZO). We investigate BZO of a neutral cold atom in an optical cavity pumped by a laser. We find that the single mode electromagnetic field of the optical cavity is affected by the atomic dynamics and propose the idea that a measurement of the electromagnetic field leaking out of the cavity will reflect the BZO frequency WB = Fd/h, and can be used for a precision measurement of F. The motivation for such a study comes from the fact that if the force F is gravity, then one can probe gravitational forces on sub-millimeter scales since the size of these systems are generally a few hundreds of microns. Such a study can be used to detect deviations from Newtonian gravity at short range proposed by some theories beyond the standard model of particle physics. </p> / Thesis / Master of Science (MSc)

<p>Atomic ions trapped in microfabricated surface traps can be utilized as a physical platform with which to build a quantum computer. They possess many of the desirable characteristics of such a device, including high fidelity state preparation and readout, universal logic gates, and long coherence times, and can be readily entangled with each other through photonic interconnects. The use of optical cavities integrated with trapped ion qubits as a photonic interface presents the possibility for order of magnitude improvements in performance in several key areas for their use in quantum computation. The first part of this thesis describes the design and fabrication of a novel surface trap for integration with an optical cavity. The trap is custom made on a highly reflective mirror surface and includes the capability of moving the ion trap location along all three trap axes with nanometer scale precision. The second part of this thesis demonstrates the suitability of small microcavities formed from laser ablated, fused silica substrates with radii of curvature in the 300-500 micron range for use with the mirror trap as part of an integrated ion trap cavity system. Quantum computing applications for such a system include dramatic improvements in the photon entanglement rate of up to 10 kHz, the qubit measurement time down to 1 microsecond, and the qubit measurement error rate down to the 1e-5 range. The final part of this thesis describes a performance simulator for exploring the physical resource requirements and performance demands to scale a quantum computer to sizes capable of implementing quantum algorithms beyond the limits of classical computation.</p> / Dissertation

This thesis presents a theoretical study of the collective effects of a large number of photon emitters coupled to optical cavities. The ensemble effects are accounted for by considering both the light emitting and scattering by the photon emitters. It suggests that, to correctly estimate the emitters ensemble coupled cavity mode, it is necessary to consider the existence of the excited excitons ensemble and optical pumps. This thesis shows that optical pumps can excite more excitons and scattering channels as pumping power increases. The change in exciton population can lead to comprehensive spectral behaviors by changing the cavity spectral shapes, bandwidth and resonance positions, through the inhomogeneous broadening and frequencies repulsion effects of collective emissions. The existence of the exciton ensemble can also enhance optical coupling effects between target excitons and the cavity mode. The target exciton, which has a relatively large coupling strength and is close to the cavity peak, can affect the properties of the background dipoles and their coupling to the cavity. All these collective effects are sensitive to the number, the resonances distribution, and the optical properties of the background excitons in the frequency domain and the property of the target exciton, if any. This study provides a perspective on the control of the optical properties of cavities and individual excitons through collective excitation. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2012-07-30 14:51:15.914

Orientador: Flávio Caldas da Cruz / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-30T20:50:45Z (GMT). No. of bitstreams: 1 IngaCaqui_MarvynWilliam_M.pdf: 57466489 bytes, checksum: e14e1adbe90a64e5b5e7ee380f180702 (MD5) Previous issue date: 2016 / Resumo: Neste trabalho desenvolvemos uma montagem óptica para realizar espectroscopia de alta sensibilidade através de medidas do tempo de decaimento da luz em uma cavidade óptica contendo uma amostra transparente (ring-down time spectroscopy). Usando um laser contínuo de comprimento de onda único em S32nm e uma cavidade de finesse moderada (16500), optamos por explorar o uso deste sistema para análise de amostras líquidas ou sólidas, ao invés do uso tradicional em espectroscopia de gases. Para isto utilizamos uma cubeta comercial intracavidade, com faces orientadas em ângulo de Brewster, para estudo de amostras líquidas. Uma análise das perdas residuais por reflexão nas faces foi realizada a fim de extrair o coeficiente de absorção do líquido. Demonstramos também o uso deste sistema para medidas de pequenos coeficientes de absorção de sólidos transparentes / Abstract: In this work, an experimental optical setup for high sensitivity ring-down time spectroscopy was developed. This is based on measurements of the light decay time in an optical cavity containing a transparent sample. Using a continuous-wave, single-wavelength laser at 532 nm and an optical cavity of moderate finesse (16500), we opted for exploring this system for analysis of liquid and solid samples, instead of the traditional use in gas spectroscopy. For this, an intracavity commercial cuvette with faces oriented at Brewster's angle was used for the study of liquid samples. An analysis of the limitations arising from the residual losses by reflection on the faces was carried out, in order to extract the absorption coefficient of the liquid. The usefulness of this system for measurements of the small absorption coefficients of transparent solids was also demonstrated / Mestrado / Física / Mestre em Física / 1186373/2013 / CAPES

Le cœur du travail de notre groupe est l'étude de la réaction de photodétachement, qui consiste en l'expulsion de l'électron excédentaire d'un ion négatif lors de l'absorption d'un photon. Ce travail de thèse s'articule autour de deux projets : la microscopie de photodétachement, technique d'interférométrie électronique permettant de produire des données spectroscopiques sur les ions négatifs ; et le projet SIPHORE qui envisage la neutralisation d'un jet rapide d'ions négatifs à partir de la réaction de photodétachement, dans le but de servir la maîtrise de la fusion thermonucléaire contrôlée. Les évolutions de ces deux projets se recoupent dans la nécessité d'augmenter le nombre d'événements de photodétachement produits en un temps donné. Ce travail a permis d'étudier et de mettre en place différentes techniques expérimentales pour réaliser l'amplification de la réaction de photodétachement. Notre montage nous permet de produire cette réaction dans une zone d'interaction formée par l'intersection d'un jet d'ions et d'un faisceau laser. Nous envisageons d'une part la modification de la section efficace de photodétachement lorsque la réaction est produite en présence d'un champ magnétique, d'autre part l'amplification du flux de photons dans la zone d'interaction par stockage de lumière en cavité optique. Les avancées réalisées ouvrent de nouvelles perspectives sur les études fondamentales et les applications techniques liées aux ions négatifs. / The core of the work of our group is the photodetachment reaction, which consists in the expulsion of the extra electron of a negative ion by the absorption of a photon. This thesis work is organised around two projects: the photodetachment microscopy, an electron interferometric technique which produces spectroscopic data on negative ions; and the SIPHORE project which considers the neutralization of a fast negative ions beam by the help of the photodetachment process, for the purpose of controlled thermonuclear fusion. The evolutions of these two projects are overlapping in the need of increasing the number of photodetachment events produced per unit of time. This work has led to the study and the implementation of several experimental techniques to realise the amplification of the photodetachment reaction. Our setup permits to produce this reaction in an interaction area formed by the intersection of a negative ions beam with a laser beam. On the one hand we investigate the modification of the photodetachment cross section when the reaction is produced under a magnetic field. On the other hand we consider the amplification of the photon flux inside the interaction region using light storage with optical cavities. The results obtained pave the way towards new prospects for the fundamental studies and the technical applications affiliated with negative ions.

In this dissertation, a novel semiconductor mode-locked oscillator which is an extension of eXtreme Chirped Pulse Amplification (XCPA) is investigated. An eXtreme Chirped Pulse Oscillator (XCPO) implemented with a Theta cavity also based on a semiconductor gain is presented for generating more than 30ns frequency-swept pulses with more than 100pJ of pulse energy and 3.6ps compressed pulses directly from the oscillator. The XCPO shows the two distinct characteristics which are the scalability of the output energy and the mode-locked spectrum with respect to repetition rate. The laser cavity design allows for low repetition rate operation < 100MHz. The cavity significantly reduces nonlinear carrier dynamics, integrated self phase modulation (SPM), and fast gain recovery in a Semiconductor optical Amplifier (SOA). Secondly, a functional device, called a Grating Coupled Surface Emitting Laser (GCSEL) is investigated. For the first time, passive and hybrid mode-locking of a GCSEL is achieved by using saturable absorption in the passive section of GCSEL. To verify the present limitation of the GCSEL for passive and hybrid mode-locking, a dispersion matched cavity is explored. In addition, a Grating Coupled surface emitting Semiconductor Optical Amplifier (GCSOA) is also investigated to achieve high energy pulse. An energy extraction experiment for GCSOA using stretched pulses generated from the colliding pulse semiconductor mode-locked laser via a chirped fiber bragg grating, which exploits the XCPA advantages is also demonstrated. Finally, passive optical cavity amplification using an enhancement cavity is presented. In order to achieve the interferometric stability, the Hänsch-Couillaud Method is employed to stabilize the passive optical cavity. The astigmatism-free optical cavity employing an acousto-optic modulator (AOM) is designed and demonstrated. In the passive optical cavity, a 7.2 of amplification factor is achieved with a 50 KHz dumping rate.

No description available.

<p> The need for higher bandwidth and people's desire to be "always connected" have spurred a new era of silicon photonics. The traditional integrated electrical transmission lines have been an obstacle preventing ultra high speed communication. Using monolithic chips of integrated optoelectronic circuits from silicon provides an economic way to realize Tetra Byte/Second bandwidth in a variety of areas such as "fiber to the home" and the buses linking chips inside computer.</p> <p> The heart of such optoelectronics-silicon laser-is still in pursuit. One of the most promising approaches is the erbium doped silicon nanocrystals embedded in silica system. External photon or hot electrons injection excites the silicon nanocrystals, which then transfer their energies to nearby erbium ions to emit light at 1.55 μm wavelength range.</p> <p> In this thesis, we investigate the effects of cavity and electric field on energy transfer from Si nanocrystals (Si-nc's) to Er ions, and simulate material gain in such systems. Our results show that microcavity can enhance the Forster energy transfer and material gain, reducing the requirements for Si-nc pumping. The electric field will hinder the radiation decay of Si-nc, but we have to further explore the tunneling mechanism before concluding the overall effect of electric field. Some future work needs to be done, which will shine some light on the design of the silicon laser.</p> / Thesis / Master of Applied Science (MASc)

L’intégration des communications optiques sur puce offre de vastes promesses en termes de performances et de réduction de la puissance consommée, les canaux optiques ne souffrant pas des nombreuses limitations des canaux métalliques. De plus, l’information codée optiquement permet d’atteindre des débits de données élevés par le biais du multiplexage en longueur d’onde. Afin de conserver la compatibilité avec les composants électroniques, les communications et composants optiques doivent s’intégrer dans la filière silicium. Cependant, ce dernier matériau ne permet pas d’envisager la réalisation de certaines fonctions optiques, en particulier la source laser. D’autres matériaux doivent ainsi être intégrés pour suppléer au silicium. Mes travaux de thèse portent sur l’intégration de nanotubes de carbone sur plate-forme silicium pour la photonique. Dans ces travaux, le potentiel des nanotubes de carbone pour la réalisation de sources optiques intégrées est exploré. Dans un premier temps, je proposerai des pistes de compréhension de l’apparition du gain optique dans les nanotubes de carbone semiconducteurs par analyse des temps de vie des excitons, mesurés en spectroscopie pompe-sonde. Ces temps de vie sont sensiblement rallongés lorsque la centrifugation des nanotubes de carbone, au cours de l’extraction, est poussée à des vélocités et des temps plus longs. Une explication envisagée est la réduction du nombre de défauts à la surface des nanotubes, ces défauts se comportant comme des centres de recombinaison non-radiatifs. D’autre part, une méthode efficace d’intégration des nanotubes de carbone sur guide d’onde silicium a été proposée. Cette méthode robuste et permet d’observer le couplage de la photoluminescence des nanotubes de carbone avec le mode optique du guide d’onde. Afin d’obtenir une interaction exaltée entre mode optique et nanotube de carbone, le couplage entre les nanotubes et différentes cavités photoniques, incluant microdisques, cavités Fabry-Pérot et micro-résonateurs en anneau, a été étudié. L’emploi en particulier de résonateurs en anneau permet d’observer la structuration de la photoluminescence des nanotubes de carbone par les modes de résonance de l’anneau. Différentes configurations ont été étudiées afin de compléter la compréhension des mécanismes de couplage : micro-photoluminescence, photoluminescence guidée et photoluminescence intégrée. / On-chip optical communication may increase drastically performances and consumption of communication systems. Indeed, optical channels do not face limitations that metallics interconnects do. Even better would be the achievable data rate due to the multiplexing possibility in optics. In order to keep compatibility with electronic devices, optical components and interconnects should be built in silicon. However, this material is not suitable for some optical function, such as laser sources. Thus, there is a need to integrate alternative materials to compensate for silicon weaknesses. My PhD work focuses on integration of carbon nanotube on silicon for photonics applications. In this work, potential use of carbon nanotube for light emission function is investigated. First, I will propose clue to understand the appearance of optical gain in semiconducting carbon nanotube. Such investigation is done by mean of pump-probe experiments, where the excitons lifetimes are measured. Those lifetimes slightly increase while centrifugation time and speed is increased, during the extraction process. A possible explanation is that defect-free carbon nanotubes are selected by the centrifugation process. In parallel, I worked on designing an efficient method to couple nanotubes photoluminescence with silicon waveguides. This method appears to be quite robust, and allows to observe coupling between the nanotube photoluminescence and the optical mode of the waveguide. In order to obtain a more intense interaction between the optical mode and carbon nanotubes, I investigated the coupling between carbon nanotubes and several photonic cavities, including microdisks, Fabry-Pérot cavities and ring resonators. Specifically, ring resonators allow to measure the photoluminescence of carbon nanotube structured by the resonant modes. Several configurations are studied to understand more in-depth the coupling mechanisms: micro-photoluminescence, guided photoluminescence and integrated photoluminescence.