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Tesi sul tema "Optics"
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1
Larson, Jonas. "Extended Jaynes-Cummings Models In Cavity Qed". Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-404.
Testo completo
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Evans, Jonathan W. "Beam Switching of an Nd:YAG Laser Using Domain Engineered Prisms in Magnesium Oxide Doped Congruent Lithium Niobate". University of Dayton / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1281366442.
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Jonsson, Fredrik. "The nonlinear optics of magneto-optic media". Doctoral thesis, KTH, Physics, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2967.
Testo completo
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McLaughlin, Lisa. "Optical beam control using adaptive optics". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Dec%5FMcLaughlin.pdf.
Testo completoAbstract (sommario):
Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, December 2005.Thesis Advisor(s): Brij Agrawal, Ty Martinez. Includes bibliographical references (p. 75-76). Also available online.
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De, Matos Christiano Jose Santiago. "Nonlinear optics in specialty optical fibres". Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419770.
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Clark, Douglas F. "High frequency electro-optic modulators for integrated optics". Thesis, University of Glasgow, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293507.
Testo completo
7
Agnew, Amalia. "Quantum-Chemical Investigations of Second- and Third-Order Nonlinear Optical Chromophores for Electro-Optic and All-Optical Switching Applications". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11575.
Testo completoAbstract (sommario):
The past decades have witnessed the development of new materials with large nonlinear optical properties, which have made them attractive candidats for a broad spectrum of breakthrough applications in the electro-optic and photonic fields (e.g., telecommunication and computing). A deeper understanding of the relationship between, on the one hand, the chemical structure and, on the other hand, the electronic and (linear and nonlinear) optical properties has proven useful for the rational design of new efficient materials. Reaching such an understanding has attracted major interest in the scientific community worldwide in both academia and industry. Therefore, the development of new efficient NLO chromophores and materials along with commercial devices of high quality is helped via the establishment of multidisciplinary research teams combining: (i) the theoretical modeling using quantum-chemical computational calculations; (ii) the organic synthesis; (iii) the optical characterization; and (iv) the device fabrication. In this dissertation, quantum-chemistry is used to evaluate the second- and third-order NLO properties of series of new chromophores and take advantage of a feedback loop with the experimental team to understand the structure-property relationships.
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Llobera, Adan Andreu. "Integrated Optics Technology on Silicon: Optical Transducers". Doctoral thesis, Universitat Autònoma de Barcelona, 2002. http://hdl.handle.net/10803/3342.
Testo completoAbstract (sommario):
El camp de l'òptica integrada es presenta com un dels mes prometedors a curt-mig plaç degut als clars avantatges que presenta amb respecte de l'electrònica tradicional. El fet d'utilitzar la llum com a medi vehicular, la qual no es veu afectada per les possibles pertorbacions electromagnètiques, entre altres propietats, fan que aquest camp sigui una de les sortides mes viables als greus problemes de congestió de les vies de telecomunicacions que es preveuen en un futur proper. Per altra part, l'ús de l'òptica integrada per a la realització de sensors ofereix unes prestacions superiors a la majoria de transductors actuals: La resistència a condicions hostils, la mesura sense contacte directe i la seguretat en ambients perillosos, fan que aquests siguin de gran interès pel mon industrial.Dels diferents materials aptes per a la realització de components òptics integrats, únicament el silici, amb l'ampli bagatge de processos altament desenvolupats, derivats de la micromecanització i la microelectrònica, permet la fabricació de grans sèries a preus reduïts. Tot i que les propietats òptiques d'aquest element son limitades, la seva abundància, baix preu, elevada puresa, estabilitat química i rigidesa mecànica, fan d'aquest el substrat ideal per a la realització d'estructures híbrides, on les diferents funcions, òptiques i electròniques es combinen sobre el silici, utilitzant tècniques de muntatge superficial amb interconnexió òptica, a través de guies d'ona, dels diferents elements.
El confinament òptic amb estructures ARROW es basa en la reflexió total interna a l'interfase amb l'aire i l'elevada reflectivitat que provoquen les capes subjacents al nucli. L'índex de refracció i el gruix d'aquestes capes es sintonitza de manera que el mode fonamental presenti un mínim de pèrdues, mentre que els modes superiors pateixen una elevada atenuació. D'aquesta manera, és possible obtenir guies d'ona monomode amb tamany similar a la fibra òptica, encarregades d'injectar la llum, minimitzant les pèrdues d'inserció. Aquesta propietat fa que aquest tipus de guies siguin les candidates òptimes per a la fabricació de transductors òptics, els quals es basen en la idea que qualsevol alteració d'una propietat física o química produïda a un medi pot detectar-se a partir del canvi que produeix a las característiques de propagació de la llum a través d'ell.
En aquest treball s'han desenvolupat les eines necessàries per a la caracterització dels transductors òptics integrats: s'ha posat a punt els programes de simulació de diferències finites amb xarxa no-uniforme (NU-FDM) i el Mètode de propagació del feix (BPM), que permeten analitzar el comportament tridimensional de tota l'estructura. La tecnologia de Sala Blanca ha estat acondicionada per tal d'aconseguir els requeriments que necessitava l'Òptica Integrada. A aquest fet, l'obtenció de capes per PECVD amb diferents índexs de refracció, així com l'optimització de les tècniques de gravat RIE, han permès realitzar tota una sèrie de transductors òptics amb unes característiques notables. Les guies d'ona han estat mesurades en potència i longitud d'ona. Així, s'ha pogut comprovar com la configuració ARROW es trobava ben sintonitzada, a la longitud d'ona de treball (633nm) tant en gruix com en índex de refracció, validant la tecnologia emprada.
Gràcies als punts anteriors, s'han pogut realitzar tres tipus de transductors. El primer d'ells consisteix en un interferòmetre Mach-Zehnder (MZI), el qual basa el seu principi de funcionament en la modificació del camí òptic a una de les seves branques, obtenint un patró interferomètric. A partir d'aquest, és possible determinar la variació en la part real de l'índex de refracció. El segon transductor es basa en la modificació de la part imaginaria de l'índex de refracció. Entremig de dues guies es situa una membrana selectiva, la qual té com a característica principal la modificació de la seva transmissió, a una certa longitud d'ona, a mesura que absorbeix un determinat ió. A partir de l'atenuació mesurada al final del dispositiu, és possible conèixer la quantitat d'ions absorbits. Finalment, el tercer transductor es basa en l'obstrucció del camí òptic amb un material absorbent mòbil. La posició d'aquest absorbent ha estat dissenyada per variar amb l'acceleració, obtenint un accelerómetre òptic.
Integrated optics is one of the most interesting research fields in the short-mid term due to the clear advantages that it has as compared to the traditional electronics. Using light as the carrier of information, which is unaffected to electromagnetic perturbations, cause this field to be one of the most viable solutions concerning the telecommunications bottleneck. In addition, the application of integrated optics in the sensor field offers a better response as compared to the transducers used nowadays: Its capability to resist harsh environments, the measurement without direct contact and the safety in explosive media cause this to be of huge interest for the industry.
Between the different materials available to be used for integrated optics, only silicon, with the great knowledge of their technological aspects, allows the mass low-cost fabrication. Although its limited optical properties, its abundance, high purity, chemical stability and mechanical stiffness cause it to be ideal for hybrid integration, where the optical an electrical parts of the device are combined on silicon, using surface mounting techniques and with optical interconnection, using waveguides, between them.
The optical confinement with ARROW structures is based on the total internal reflection at the upper interface and the ultra-high reflectivity that cause the layers beneath the core. The refractive index and the thickness of these layers is tuned in such a way that the lowest order mode has a minimum of losses, while the rest of the modes suffer from high attenuation. Then, it is possible to obtain single mode waveguides with core thickness comparable to the single-moded fiber optics, minimizing the insertion losses. Then, these waveguides seem to be the most promising candidates for the fabrication of optical transducers, which are based on the idea that any variation of a physical or chemical property caused to a media can be detected form a the change that is produced on the light path across it.
In this thesis it has been developed the necessary tools to characterize the integrated optical transducers: It has been implemented the simulation programs based on non-uniform finite-difference method (NU-FDM) and the Beam propagation method (BPM), that allows analyzing the 3D behavior of any structure. The technological steps have been arranged so as to meet the integrated optics requirements. Concretely, the deposition of PECVD layers with different refractive index, together with the optimization of the RIE process, has allowed obtaining several optical transducers with excellent properties. Their waveguides have measured, both in power and in wavelength, showing that the ARROW structure was tuned in according to specifications.
With the basis of the waveguides, it has been possible to define three different optical transducers: A Mach-Zehnder Interferometer, an absorption sensor and an optical accelerometer.
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Almeida, Luis Miguel Lima de. "All-optical processing based on integrated optics". Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13705.
Testo completoAbstract (sommario):
Mestrado em Engenharia Eletrónica e TelecomunicaçõesDuring the last years, the demand for high data transfer rates in optical fiber communications has increased exponentially. Since image in its original format exactly as it is captured by the digital camera requires an enormous amount of storage capacity, it is important to develop a system that increases its amount of compression while preserving the important image’s information. In the topic of image’s compression, there are several transformation techniques used for data compression. Discrete Wavelet Transform (DWT) is one of the most commonly used, thanks to its multi-resolution transformation. This multi-resolution property allows to develop, not only a lossless compression method, from which the original image can be obtained exactly as it was before the transform, but also, a lossy method where it is not possible to obtain the original image. In this context, this thesis will develop the idea to apply the Haar wavelet transform using optical circuits. This concept will be analyzed, verifying the possibility of its implementation in the optical domain, using several methods, lossy and lossless, to conclude about the best compression method to apply to an image. Finally, the lossy method will be tested in the laboratory with different components and design the optical device able to accomplish the Haar wavelet transform.
Nos últimos anos, a procura por elevados ritmos de transferência de informação em comunicações óticas tem aumentado exponencialmente. Dado que imagem, no seu formato original exactamente como é captada pela câmara fotográfica ocupa enormes quantidades de espaço de armazenamento, torna-se importante desenvolver um sistema que aumente o seu grau de compressão, preservando as informações importantes da imagem. No tópico da compressão de imagem existem várias técnicas de transformação usadas para compressão de dados. A transformada discreta de onduleta é uma das mais usadas, graças ao uso da transformação em multiresolução. Esta propriedade de multi-resolução permite não só desenvolver métodos de compressão de imagem sem perdas, nos quais se obtém a imagem original exatamente como era antes da transformação, como também métodos com perdas, já não sendo possível obter a imagem original. Neste contexto, esta tese irá desenvolver a ideia de aplicar a transformada de onduleta de Haar usando circuitos óticos. Este conceito irá ser analisado, verificando a possibilidade da sua implementação no domínio ótico, usando vários métodos, com perdas e sem perdas, para concluir acerca do melhor método de compressão a aplicar a uma imagem. Por fim, o método com perdas irá ser testado no laboratório com diferentes componentes e desenhar o dispositivo ótico capaz de aplicar a transformada de onduleta de Haar.
10
Baker, Christopher Charles. "Electroluminescent Thin Films for Integrated Optics Applications". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1054903604.
Testo completo
11
Yan, Wei. "Manipulation of Light with Transformation Optics". Doctoral thesis, KTH, Mikroelektronik och tillämpad fysik, MAP, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-25849.
Testo completoAbstract (sommario):
Transformation optics, a recently booming area, provides people a new approach to design optical devices for manipulating light. With transformation optics, a lot of novel optical devices are proposed, such as invisibility cloaks, optical wormholes, optical black holes, illusion devices. The present thesis is devoted to investigate transformation optics for manipulating light. Firstly, an introduction to transformation optics is given. This part includes: (1) introducing differential geometry as the mathematical preparation; (2) expressing Maxwell’s equations in an arbitrary coordinate system and introducing the concept of transformation media as the foundation stone of transformation optics; (3) discussing light from the geometry perspective as the essence of transformation optics; (4) showing how to use transformation optics to design optical devices. For our works on invisibility cloaks, we analyze the properties of arbitrary shaped invisibility cloaks, and confirm their invisibility abilities. The geometrical perturbations to cylindrical and spherical shaped cloaks are analyzed in detail. We show that the cylindrical cloak is more sensitive to the perturbation than a spherical cloak. By imposing a PEC (PMC) layer at the interior boundary of the cylindrical cloak shell for TM (TE) wave, the sensitivity can be reduced dramatically. A simplified non-magnetic cylindrical cloak is also designed. We show that the dominant zeroth order scattering term can be eliminated by employing an air gap between the cloak and the cloaked region. We propose a compensated bilayer by a folding coordinate transformation based on transformation optics. It is pointed out that complementary media, perfect negative index lens and perfect bilayer lens made of indefinite media are well unified under the scope of the transformed compensated bilayer. We demonstrate the applications of the compensated bilayer, such as perfect imaging and optical illusion. Arbitrary shaped compensated bilayers are also analyzed. Nihility media known as the media with ε =μ= 0, are generalized from transformation optics as transformation media derived from volumeless geometrical elements. The practical constructions of nihility media by metamaterials are discussed. The eigen fields in the nihility media are derived. The interactions between an external incident wave and a slab of nihility media in the free space background are analyzed. A new type of transformation media called α media is proposed for manipulating light. Light rays in the α media have a simple displacement or rotation relationship with those in another media (seed media). Such relationship is named α relationship. The α media can be designed and simplified to a certain class of diagonal anisotropic media, which are related to certain isotropic media by the α relationship. Several optical devices based on the α transformation media are designed. Invisibility cloaks obtained from the coordinate transformation approach are revisited from a different perspective.QC 20101102
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Haskell, Adam Benjamin. "A Durability and Utility Analysis of EFPI Fiber Optic Strain Sensors Embedded in Composite Materials for Structural Health Monitoring". Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/HaskellAB2006.pdf.
Testo completo
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Hessenius, Chris. "Novel Cavities and Functionality in High-Power High-Brightness Semiconductor Vertical External Cavity Surface Emitting Lasers". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/301667.
Testo completoAbstract (sommario):
Ever since the first laser demonstration in 1960, applications for laser systems have increased to include diverse fields such as: national defense, biology and medicine, entertainment, imaging, and communications. In order to serve the growing demand, a wide range of laser types including solid-state, semiconductor, gas, and dye lasers have been developed. For most applications it is critical to have lasers with both high optical power and excellent beam quality. This has traditionally been difficult to simultaneously achieve in semiconductor lasers. In the mid 1990's, the advent of an optically pumped semiconductor vertical-external-cavity surface-emitting laser (VECSEL) led to the demonstration of high (multi-watt) output power with near diffraction limited (TEM00) beam quality. Since that time VECSELs covering large wavelength regions have been developed. It is the objective of this dissertation to investigate and explore novel cavity designs which can lead to increased functionality in high power, high brightness VECSELs. Optically pumped VECSELs have previously demonstrated their potential for high power, high brightness operation. In addition, the "open" cavity design of this type of laser makes intracavity nonlinear frequency conversion, linewidth narrowing, and spectral tuning very efficient. By altering the external cavity design it is possible to add additional functionality to this already flexible design. In this dissertation, the history, theory, design, and fabrication are first presented as VECSEL performance relies heavily on the design and fabrication of the chip. Basic cavities such as the linear cavity and v-shaped cavity will be discussed, including the role they play in wavelength tuning, transverse mode profile, and mode stability. The development of a VECSEL for use as a sodium guide star laser is presented including the theory and simulation of intracavity frequency generation in a modified v-cavity. The results show agreement with theory and the measurement of the sodium D1 and D2 lines are demonstrated. A discussion of gain coupled VECSELs in which a single pump area accommodates two laser cavities is demonstrated and a description of mode competition and the importance of spontaneous emission in determining the lasing condition is discussed. Finally the T-cavity configuration is presented. This configuration allows for the spatial overlap of two VECSEL cavities operating with orthogonal polarizations. Independent tuning of each cavity is presented as well as the quality of the beam overlap and demonstration of Type II intracavity sum frequency generation. Future applications to this configuration are discussed in the generation of high power, high brightness lasers operating from the UV to far-infrared and even terahertz regimes.
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MOSHREFZADEH, ROBERT SHAHRAM. "THEORY AND FABRICATION OF SUB-MICRON GRATINGS ON NONLINEAR OPTICAL WAVEGUIDES". Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184138.
Testo completoAbstract (sommario):
Because of their compatibility with the planar concept of integrated optics, grating couplers offer the most satisfactory means of coupling light into thin film optical waveguides. The purpose of this dissertation has been to study the behaviour, both theoretically and experimentally, and fabrication of grating couplers in nonlinear waveguides. A theory of nonlinear grating couplers is presented based on a coupled-mode approach. The dependence of coupling efficiency on incident beam intensity, beam size, beam position, incident angle, chirp rate, and waveguide losses have been examined all in the presence of nonlinearities in the waveguide. It is reported that, in the presence of nonlinearities, the coupling efficiency decreases with increasing incident power. Different ways of optimizing the coupling efficiency at high incident power levels are presented. These include adjusting the beam size, the coupling angle, and chirping the grating. A new technique is reported for fabrication of regular period, chirped, and curved photoresist gratings. The experimental arrangement is essentially based on Lloyd's mirror fringes and is characterized by its stability, simplicity, and versatility. We also report on successful use of Reactive Ion-Beam Etching (RIBE) with C₂F₆ gas in producing very smooth and deep gratings with high aspect ratios in different waveguide structures. Experimental coupling efficiencies of up to 40% are reported in polystyrene waveguides using etched grating couplers. Experiments are reported in support of the theoretical findings of this dissertation using a polystyrene waveguide with thermal nonlinearity.
15
Tomljenovic-Hanic, Snjezana. "Propagation effects in optical waveguides, fibres and devices /". View thesis entry in Australian Digital Theses Program, 2003. http://thesis.anu.edu.au/public/adt-ANU20040921.104741/index.html.
Testo completo
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Mocking, Tijs. "Studies of Nanostructured Layers with UV-VIS Spectroscopic Ellipsometry". Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-12053.
Testo completoAbstract (sommario):
In this report a model analysis is presented for three different nanostructured layers: silicon nanotips (SiNTs), gold nanosandwiches and Split Ring Resonators (SRR). The last two materials are metamaterials and both may show a negative refraction index. Experimental data are obtained for every sample using a variable angle spectroscopic ellipsometer. For the gold nanosandwiches, also an infrared ellipsometric measurement is done. For complex layers like these, advanced modeling is necessary. A recently developed analysis program including options for both anisotropic permittivity and permeability is used. A realistic model is presented in this report for the gold nanosandwiches, which also includes the magnetic activity in the layer itself. The results for the nanosandwiches are reasonable, and a magnetic oscillation is found in the horizontal plane at around 260 nm although it was not expected to have a resonance that far in the UV-range. For the SiNTs and the SRR it was not possible to create an acceptable model.
17
Li, Qiang. "Silicon Based Photonic Devices and Their Applications". Doctoral thesis, KTH, Fotonik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-31290.
Testo completoAbstract (sommario):
The integration of modern electronic devices for information processing is rapidly ap-proaching an interconnect bottleneck. Silicon photonics can be a promising solution forcircumventing this bottleneck, as already being anticipated by many electronics manu-facturers including HP, IBM and Intel. In particular, optical interconnects can expeditedata transfer both between and within microchips. This thesis aims at two basic buildingblocks of silicon photonics: waveguides and resonators and addresses their applications inoptical signal processing and their potential integration with plasmonic devices. Firstly, the basic theories of waveguide and resonator are introduced. For a singleresonator which acts as a basic signal processing unit, the transmission, phase shift andgroup delay exhibit unique characteristics. Mode splitting is observed in both a singleresonator and a coupled-resonator system. By tuning the configuration of the coupled-resonator system, one can obtain different transmission characteristics for more advancedsignal processing. Secondly, the fabrication and characterization of silicon waveguides and resonatorsused in the thesis are introduced. The fabrication is carried out with e-beam lithographyfollowed by inductively coupled plasma etching. A vertical grating coupling method isadopted to characterize the transmission spectrum. Thirdly, based on a single-ring resonator, three kinds of signal processing are ex-perimentally demonstrated: (1) 10 Gb/s format conversion from non-return-to-zero toalternate-mark-inversion signal; (2) a microwave photonic phase shifter providing a tun-able phase shift of 0–4.6 rad for a 20 GHz signal; (3) a delay line providing maximaldelay times of 80 ps, 95 ps, 110 ps and 65 ps, respectively, for signals in return-to-zero,carrier-suppressed return-to-zero, return-to-zero duobinary, and return-to-zero alternate-mark-inversion formats. Fourthly, based on a single-ring resonator with mode-splitting, two kinds of signalprocessing are experimentally demonstrated: (1) a dense wavelength conversion using thefree carrier dispersion effect with a data rate ranging from 500 Mb/s to 5 Gb/s; (2) amaximum pulse advancement of 130 ps for a 1 ns signal pulse. Since silicon photonic devices are limited by diffraction limit, we further look intotheir hybridization with the diffraction-limit-free plasmonic devices. Two directional cou-plers from a Si photonic waveguide to a hybrid Si-metal plasmonic waveguide and to ametal-insulator-metal plasmonic waveguide are investigated. The proposed hybrid cou-plers feature a short coupling length, a high coupling efficiency, a high extinction ratioand a low insertion loss.QC 20110315
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Rydberg, Sara. "Rare Earth elements in optical materials and design of high power ytterbium fiber laser for frequency doubling using nonlinear ppKTP crystal". Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-36138.
Testo completo
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Olitzky, Joshua D. "Time and Frequency Resolved Pump Probe Spectroscopy and Growth of Near Surface Quantum Confined Semiconductors Coupled to Metallic Nanostructures". Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/595980.
Testo completoAbstract (sommario):
Metallic nano-structures provide for new and exciting domains to investigate light-matter interactions. The coupling of these metallic nano-structures to semiconductor emitters allows for the observation of cavity QED effects including Purcell enhancement and Vacuum Rabi splitting. The focus of this dissertation will be to present an introduction and background to semiconductor optics, and metallic metamaterial systems. This will be followed by the presentation of the spectroscopy systems designed and constructed during my tenure as graduate student and the experimental data obtained with these systems. Some of the results have been published, while some of the presented material is still actively being pursued for publication. More specifically, the dissertation will cover the research at hand, experimental techniques, and results.
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Semenets, V. V., M. V. Neofitnyy, Yu P. Machekhin, O. S. Hnatenko, V. I. Zarytskyi e S. V. Gulak. "Laser system for recording optics". Thesis, CAOL, 2019. http://openarchive.nure.ua/handle/document/15098.
Testo completoAbstract (sommario):
The development of a modern laser system for recording optics is presented in this research paper. Studying optical components for designing this system by various methods, by calculated methods and by a method of using modern modeling package Zemax, was conducted. The results of the calculations and simulation, which led to the preliminary design of the laser system of optics registration, coincide.
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Novikova, Irina Borisovna. "Nonlinear magneto-optic effects in optically dense Rb vapor". Texas A&M University, 2004. http://hdl.handle.net/1969.1/364.
Testo completoAbstract (sommario):
Nonlinear magneto-optical effects, originated from atomic coherence, are studied both theoretically and experimentally in thermal Rb vapor. The analytical description of the fundamental properties of coherent media are based on the simplified three- and four-level systems, and then verified using numerical simulations and experimental measurements. In particular, we analyze the modification of the long-lived atomic coherence due to various physical effects, such as reabsorption of
spontaneous radiation, collisions with a buffer gas atoms, etc. We also discuss the importance of the high-order nonlinearities in the description of the polarization rotation for the elliptically polarized light. The effect of self-rotation of the elliptical polarization is also analyzed.
Practical applications of nonlinear magneto-optical effects are considered in precision metrology and magnetometery, and for the generation of non-classical states of electromagnetic field.
22
An, Dechang. "Electro-optic polymer-based monolithic waveguide devices with multi-functions of amplification switching and modulation". Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3035933.
Testo completo
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Tsangaris, Charalambos. "Transverse effects in optical cavities and nonlinear optics". Thesis, Imperial College London, 2005. http://hdl.handle.net/10044/1/8799.
Testo completo
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Norris, Greg. "Experimental nonlinear optics for applications in optical microscopy". Thesis, University of Strathclyde, 2011. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=16932.
Testo completoAbstract (sommario):
The motivation of this thesis was to develop efficient and improved optical excitation sources for applications in confocal laser scanning microscopy (CLSM) and multiphoton laser scanning microscopy (MPLSM), with emphasis on extending the wavelength coverage of existing laser sources using nonlinear optical methods. This included quantitative and qualitative structural analysis of periodically poled nonlinear materials using MPLSM. These materials, used in nonlinear optical frequency conversion, rely upon consistent poling lengths for quasi-phase matched operation. The described technique provided a non-destructive assessment of inhomogeneities within the crystal structure, which may impact upon frequency conversion efficiency processes. Following this analysis, innovative pump geometries were investigated for ultra-short pulsed singly resonant synchronously pumped optical parametric oscillators (SPOPOs). Through application of a novel bi-directional pump geometry, an increase in peak power of up to 90 % was observed, with peak powers in excess of 18.8 kW generated. This substantially outperformed any pump geometry previously implemented. This source was then applied to three photon laser scanning microscopy. Next, a visible, wavelength tunable, ultra-short pulsed source based on sum frequency mixing was developed for MPLSM at wavelengths shorter than 700nm. With average output power of ~ 150 mW, the source was applied to MPLSM of biological and non-biological UV excitable samples and results were compared with the longer wavelength Ti:Sappphire system. Finally, a SC source and Ti:Sapphire laser were applied for optical beam induced current (OBIC) microscopy of an InGaN LED to provide information regarding the spectral response of the diode and imaging of the active region. This provided additional information regarding inhomogeneity and hence efficiency.
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Petrauskas, Marius. "Bendrosios optikos kursas su "Mathematica"". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050616_162052-47030.
Testo completoAbstract (sommario):
This is the short course of optics. Work contains 19 subjects about diffraction, interference, electromagnetic wave, geometry optics, anisotropy, and refraction index. This work is a source for extended individual study of general optics for any student who wants information about this topic. The objective that we want to complete doing this section is to be a help for the student increasing his knowledge about the topic. Each subject has the links to interactive program (user-friendly “ Mathemtica” scripts), which are related directly to the text of the subject. This work will be invaluable to advanced undergraduates, graduate students working in most areas of optics.
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Jedrkiewicz, Ottavia. "Theories of atom-field interaction in cavities and retrodiction for quantum communications". Thesis, University of Essex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340589.
Testo completo
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Kim, Dae Wook, Chang-jin Oh, Andrew Lowman, Greg A. Smith, Maham Aftab e James H. Burge. "Manufacturing of super-polished large aspheric/freeform optics". SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622422.
Testo completoAbstract (sommario):
Several next generation astronomical telescopes or large optical systems utilize aspheric/freeform optics for creating a segmented optical system. Multiple mirrors can be combined to form a larger optical surface or used as a single surface to avoid obscurations. In this paper, we demonstrate a specific case of the Daniel K. Inouye Solar Telescope (DKIST). This optic is a 4.2 m in diameter off-axis primary mirror using ZERODUR thin substrate, and has been successfully completed in the Optical Engineering and Fabrication Facility (OEFF) at the University of Arizona, in 2016. As the telescope looks at the brightest object in the sky, our own Sun, the primary mirror surface quality meets extreme specifications covering a wide range of spatial frequency errors. In manufacturing the DKIST mirror, metrology systems have been studied, developed and applied to measure low-to-mid-to-high spatial frequency surface shape information in the 4.2 m super-polished optical surface. In this paper, measurements from these systems are converted to Power Spectral Density (PSD) plots and combined in the spatial frequency domain. Results cover 5 orders of magnitude in spatial frequencies and meet or exceed specifications for this large aspheric mirror. Precision manufacturing of the super-polished DKIST mirror enables a new level of solar science.
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Churin, Dmitriy. "Development of Ultrafast Fiber Laser Sources". Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/579113.
Testo completoAbstract (sommario):
The development of high average and peak power ultrashort pulsed fiber lasers is important for many critical research, industrial, and defense applications. However, the performance of mode-locked fiber oscillators still lags behind that of solid-state counterparts such as Kerr-lens mode-locked Ti:sapphire lasers. Despite the drawbacks in cost, size and required maintenance, Ti:sapphire remains the workhorse of ultrafast science. One of the remaining challenges for fiber lasers to overcome is their limited set of accessible wavelengths. Unfortunately, readily available ytterbium, erbium and thulium fiber lasers can produce coherent radiation only near 1, 1.55 and 2μm, respectively. There remain a significant number of wavelength regions that fiber lasers cannot address. In this thesis, novel fiber lasers producing ultrashort pulses at wavelengths not currently accessible with established active rare-earth-doped fibers are investigated. Our main approach is to use various nonlinear optical effects to generate new laser wavelengths. First, a watt-level synchronously pumped Raman fiber oscillator generating tens of nanojoules femtosecond pulses is demonstrated. Stimulated Raman scattering in a passive fiber within an oscillator cavity allows formation of Raman pulses that are spectrally redshifted with respect to the pump pulses. World-record output pulse energy and conversion efficiency have been achieved with our femtosecond Raman fiber laser design. We have also demonstrated a high power, widely tunable all-fiber optical parametric oscillator (FOPO) based on four-wave mixing in a passive fiber. The FOPO is synchronously pumped with an Yb³⁺-doped mode-locked fiber laser working at ~1040nm. The FOPO produces ultrashort pulses tunable from 760 to 1560nm. Record pulse energy is generated at the output of the femtosecond FOPO. Depending on the configuration of the FOPO, the duration of produced pulses varies between 170fs and 3ps. This new laser source has similar performance to standard Ti:sa femtosecond lasers so it can potentially replace the latter in many applications. Ultrashort optical pulses in the mid-IR and long-IR range (2-20 μm) have many important applications in gas sensing, counter-measures, etc. The realization of the ultrashort pulses in the mid-IR and long-IR wavelengths requires the use of free-space nonlinear crystals. An efficient mid-IR source based on difference frequency generation (DFG) in an AgGaS₂ crystal using femtosecond erbium/thulium pump fiber laser has been proposed and demonstrated. The photon conversion efficiency of the pump wave (1.55μm) to idler wave (9.2μm) has been measured to be 16%, which is today a record for conversion of near-IR light radiation from fiber lasers to 9μm spectral range. Potentially the photon conversion efficiency can be increased up to 60% by using pump pulses having higher peak power. Finally, generation of supercontinuum (SC) light in the mid-IR spectral range is also demonstrated. It is well known that SC produced in standard optical fibers is limited to ~6μm by material absorption. The liquid core optical fiber platform has been proposed to address this matter. Several highly nonlinear liquids have minimal absorption in the mid-IR wavelength range, which potentially allows us to create broadband SC light in this spectral region. SC generation up to 2.4μm in an integrated hollow core optical fiber filled with CS₂ has been demonstrated. Further development of the liquid core optical fiber platform should allow generation of the SC covering wavelengths beyond 6μm.
29
Brunton, Adam North. "MCP optics". Thesis, University of Leicester, 1994. http://hdl.handle.net/2381/35847.
Testo completoAbstract (sommario):
This thesis is an account of research into a novel type of X-ray optic - the microchannel plate (MCP). Experiments to determine the point to point focusing properties of square pore MCPs manufactured by Galileo Electro-Optics and Philips Photonics are reported. These were performed both in a test chamber at Leicester with an electron-bombardment X-ray source and with a laser-plasma X-ray source at the Rutherford Appleton Laboratory. A resolution of 6 arcmin and an intensity gain of 20 were recorded using a Galileo focusing MCP. An invesigation into the focusing action of MCPs which have been curved to a spherical figure is detailed. Such curved MCPs may, in a manner reminiscent of a conventional refractive lens, be used to focus a parallel X-ray beam to a point forming the basis of an X-ray telescope, or conversely to convert the diverging beam from a point-like X-ray source to a quasi-parallel one. The curving experiments were performed by Philips Photonics on standard circular pore MCPs. Tests on these plates were performed at Leicester; the results appear favourable. The technique has been applied to MCPs of up to 4mm thickness, curving them to a radius of 1.4m (0.7m focal length). A comprehensive Monte Carlo ray-tracing model is presented. This was initially developed to facilitate an understanding of the geometry of MCP focusing and to produce idealised images corresponding to a given experimental set up. These perfect images may be compared with, or used to predict experimental results. Comparison with experimental results led to incorporation of MCP distortions into the code. These distortions have been found by a programme of metrology which is also described. The model has led to a clear insight into the causes of poor image quality and their relative importance.
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Brent, Joshua Ian, Matthew Barnum, Saul Corrales, Nan Ding, Katherine Green e Lena Wolfe. "Computational Optics". Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/243895.
Testo completoAbstract (sommario):
Many aerospace sensor platforms have a fixed opto-mechanical layout due to harsh environmental conditions. This design decision results in tight opto-mechanical tolerances. Computational optics is a technology that is currently used in the commercial market, but has yet to be implemented in the defense industry. By using this methodology, the system will aim to reduce production cost by investing in non-recurring engineering (NRE) investments. This project aims to implement a proof of concept of computational optics to improve image quality while increasing depth of focus using wavefront coding.
31
Hašek, Jaroslav. "Laserový vysílač s optickým vláknem". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217799.
Testo completoAbstract (sommario):
This master´s thesis deals with communication which is provided by optical devices. Optical wireless links are enforced due to high bit rate, responsibility and noise immunity. Main part of this master´s project is devoted to optical fibre, its characteristic and its usage in laser transmitter.
32
Evans, Christopher Courtney. "Nonlinear optics in titanium dioxide: from bulk to integrated optical devices". Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11167.
Testo completoAbstract (sommario):
In this thesis, we explore titanium dioxide (TiO2) for ultrafast, on-chip nonlinear optics by studying it in bulk, thin films, and in integrated nonlinear optical devices. TiO2's large nonlinear index of refraction (30 times that of silica) and low two-photon absorption can enable all-optical switching, logic, and wavelength conversion across wavelengths spanning the telecommunications octave (800–1600 nm). In addition, its high linear index of refraction can enhance optical confinement down to nano-scale dimensions and facilitate the tight waveguide bends necessary for dense on-chip integration. Throughout this thesis, we develop TiO2 as a novel on-chip nonlinear optics platform.Engineering and Applied Sciences
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Fu, Ling. "Fibre-optic nonlinear optical microscopy and endoscopy". Australasian Digital Thesis Program, 2007. http://adt.lib.swin.edu.au/public/adt-VSWT20070521.155004/index.html.
Testo completoAbstract (sommario):
Thesis (PhD) - Swinburne University of Technology, Faculty of Engineering and Industrial Sciences, Centre for Micro-Photonics, 2007.A thesis submitted for the degree of Doctor of Philosophy, Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, 2007. Typescript. Bibliography: p. 146-162.
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Villalaz, Ricardo A. "Volume Grating Couplers for Optical Interconnects: Analysis, Design, Fabrication, and Testing". Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-07102004-165012/unrestricted/villalaz%5Fricardo%5Fa%5F200407%5Fphd.pdf.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--School of Electrical and Computer Engineering, Georgia Institute of Technology, 2005. Directed by Thomas Gaylord.Glytsis, Elias, Committee Co-Chair ; Buck, John, Committee Member ; Kohl, Paul, Committee Member ; Adibi, Ali, Committee Member ; Gaylord, Thomas, Committee Chair. Vita. Includes bibliographical references.
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Gedaminienė, Edita. "Elektroninė informacinė priemonė "Optiniai prietaisai"". Bachelor's thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110804_085440-38038.
Testo completoAbstract (sommario):
Darbe, naudojantis informacinėmis technologijomis, sukurta elektroninė informacinė priemonė, nagrinėjanti optinius prietaisus, jų veikimo principus bei panaudojimą praktikoje. Medžiaga pateikiama tinklalapio forma internetinėje svetainėje adresu http://optometrija.3v.lt.In the work using information technologies an electronic information tool was created, which deals with optical devices, their working principles and use in practice. The material presented in the form of an online website at http://optometrija.3v.lt.
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Davis, Donald D. Jr. "Long-period fiber gratings fabricated with focused CO₂ laser pulses". Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/15764.
Testo completo
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McAlister, Daniel Frank. "Measuring the classical and quantum states and ultrafast correlations of optical fields /". view abstract or download file of text, 1999. http://wwwlib.umi.com/cr/uoregon/fullcit?p9948024.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Oregon, 1999.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 197-201). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9948024.
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Awad, Hazem. "Competitive optics circuits for all-optical signal-processing applications". Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27221.
Testo completoAbstract (sommario):
This thesis details the simulation and experimental validation of several all-optical signal-processing configurations that utilise competitive optics principles. Competitive optics refers to any number of optical systems where different optical modes or wavelengths compete for a limited system resource, such as the optical gain of some common gain medium, in order to receive amplification. The gain medium can utilise different materials including photorefractive materials (e.g. BaTO3 crystals) and saturated gain material (e.g. semiconductor optical amplifiers). Competitive optics configurations are capable of sophisticated all-optical signal processing functions ranging from all-optical wavelength conversion to optical logic and storage.
This thesis will present a series of simulated competitive optics configurations that utilise a semiconductor ring laser a basic competitive optics structure. These simulations will prove the viability and validity of competitive optics configurations that utilise saturated gain material, specifically the Semiconductor Optical Amplifier. The thesis will demonstrate the application of the Lotka-Volterra mathematical model of competitive interactions to the modelling of some of aforementioned configurations. Finally, experimental investigations of different semiconductor ring lasers configurations are presented and analysed from a competitive optics point of view.
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Ayachitula, Rajani. "Atom Optics Using an Optical Waveguide-Based Evanescent Field". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276669685.
Testo completo
40
Bauman, Brian Jeffrey. "Optical design for extremely large telescope adaptive optics systems". Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280465.
Testo completoAbstract (sommario):
Designing an adaptive optics (AO) system for extremely large telescopes (ELT's) will present new optical engineering challenges. Several of these challenges are addressed in this work, including first-order design of multi-conjugate adaptive optics (MCAO) systems, pyramid wavefront sensors (PWFS's), and laser guide star (LGS) spot elongation. MCAO systems need to be designed in consideration of various constraints, including deformable mirror size and correction height. The y,ȳ method of first-order optical design is a graphical technique that uses a plot with marginal and chief ray heights as coordinates; the optical system is represented as a segmented line. This method is shown to be a powerful tool in designing MCAO systems. From these analyses, important conclusions about configurations are derived. PWFS's, which offer an alternative to Shack-Hartmann (SH) wavefront sensors (WFS's), are envisioned as the workhorse of layer-oriented adaptive optics. Current approaches use a 4-faceted glass pyramid to create a WFS analogous to a quad-cell SH WFS. PWFS's and SH WFS's are compared and some newly-considered similarities and PWFS advantages are presented. Techniques to extend PWFS's are offered: First, PWFS's can be extended to more pixels in the image by tiling pyramids contiguously. Second, pyramids, which are difficult to manufacture, can be replaced by less expensive lenslet arrays. An approach is outlined to convert existing SH WFS's to PWFS's for easy evaluation of PWFS's. Also, a demonstration of PWFS's in sensing varying amounts of an aberration is presented. For ELT's, the finite altitude and finite thickness of LGS's means that the LGS will appear elongated from the viewpoint of subapertures not directly under the telescope. Two techniques for dealing with LGS spot elongation in SH WFS's are presented. One method assumes that the laser will be pulsed and uses a segmented micro-electromechanical system (MEMS) to track the LGS light subaperture by subaperture as the light is returned from the upward-propagating laser pulse. A second method can be used if the laser is not pulsed. A lenslet array is described which creates "pixels" which are aligned with the axes of the elongated spot of each subaperture, without requiring special charge-coupled devices (CCD's).
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Mari, Elettra. "Optical vortex diffractive optics for terrestrial and space applications". Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422490.
Testo completoAbstract (sommario):
Optical vortices are topological dislocations due to phase singularities in light beams carrying orbital angular momentum (OAM). The wavefront of the electromagnetic wave that carries OAM is twisted around its axis of propagation, with a helicoidal shape. Along the axis of the helicoid the phase is undefined, so the waves cancel each other out. Hence, the intensity distribution of a vortex presents a dark core due to the destructive interference, that is surrounded by a ’ring of light’. The vortex is characterized by a number, called the topological charge that indicates how many 2π-twists the wave does around the axis within one wavelength.
In the past decade, the OAM of a beam was paid great attention in many applications in physics. Among these, the most promising are those in optical communications, nanotechnolo- gies, biology and astronomy.
Optical vortices may be created by a variety of different methods, one of which is by the use of a diffractive vortex mask, the spiral phase plate. The spiral phase plate is a helicoidal device that looks like a spiral staircase with a certain number of steps, that imposes an azimuthally dependent phase retard on an incident optical wavefront.
The object of the research presented in this dissertation is the study of the properties of these particular optical devices and some of their possible applications.
Firstly, we have studied the spiral phase plate in the visible domain. We have found, through numerical simulations and experimental test on optical bench, a relationship between the number of steps, which build the phase gap, and the topological charge imposed to incident light beam.
This result allowed us to optimize the design parameters of the spiral phase plates manufac- tured on PMMA for astronomical purpose. We have assembled our first prototype of the optical vortex coronagraph inserting in the optical path the spiral phase plate. Coronagraphs are instru- ments designed to block the light from a bright source so that nearby much fainter sources can be directly imaged without glare. The optical vortex coronagraph exploits the dark area in the intensity distribution of the even-topologically charged optical vortices produces by spiral phase plate, attenuating the light of the bright source keeping intact that of secondary sources.
In this framework of our project we performed coronagraphic tests at Asiago 122 cm tele- scope extinguishing the light of one component of a stellar double system of almost one order of magnitude. The astronomical use of the spiral phase plate has suggested to us to investigate the efficiency
of this device with respect to the angular distance at which the secondary source crosses the central singularity. Through numerical simulations we found that the optical vortex coronagraph works also above the limit posed by the Rayleigh criterion. The research has led to the proposition of a new method to determine the angular separation between two sources above sub-Rayleigh condition, exploiting the asymmetric intensity distribution of the OVs produced by a double system that crosses spiral phase plate.
As Maxwell’s equations are equally valid for all the bandwidths, optical vortices can be pro- duced also in radio frequencies. Based on this fundamental principle, we have studied diffractive optics also for radio domain, presenting the first experimental evidence of a radio vortex. We built a reflective spiral phase plate made on styrofoam and aluminum, with a design based on the re- sults obtained in the visible domain. The experimental verification that OAM-carrying beams can be generated and exploited by using radio techniques has opened the way to the experiment that we carried out in radio communication.
We have showed, in a real-world setting, that is possible to simultaneously transmit two radio channels on the same frequency encoded in two different orbital angular momentum states. This novel radio technique allows, in principle, the implementation of an infinite number of channels in a band centered on one and the same frequency. Our experimental findings that electromagnetic OAM can be used for radio and TV transmission are likely to open new perspectives on wireless communications and radio-based science.I vortici ottici, sono caratteristiche topologiche dell’onda, legate alle singolaritá di fase nei campi elettromagnetici che trasportano momento angolare orbitale (OAM). Il fronte d’onda ha forma elicoidale, si attorciglia spiraleggiando attorno all’asse di propagazione in cui la fase é indefinita. Lungo l’asse dell’elica le onde fanno interferenza distruttiva le une con le altre, con il risultato di una distribuzione d’intensitá caratterizzato da una regione buia nel centro, circondata da luce a forma di ciambella. I vortici ottici sono caratterizzati da un valore, detto carica topologica che indica quante volte la fase compie una completa variazione di 360 gradi attorno all’asse ottico in una lunghezza d’onda. I vortici ottici possono essere prodotti con l’utilizzo di strumenti ottici. In particolare in questa tesi sono state studiate delle particolare ottiche diffrattive dette spirali di fase. Le spirali di fase sono ottiche il cui spessore cresce gradualmente intorno ad un asse; somigliano a scale a chioc- ciola, costruite con un certo numero di scalini ed impongono al fascio incidente un ritardo di fase che dipende dall’angolo azimutale. L’oggetto di questa ricerca é lo studio delle proprietá delle spirali di fase, la caratterizzazione e alcune possibili applicazioni. Lo studio si é inizialmente concentrato sulle spirali da fase nel range del visibile. Attraverso simulazioni numeriche ed esperimenti al banco ottico, siamo riusciti a ricavare una relazione tra il numero degli scalini che costruiscono il salto di fase nella spirale e la carica topologica che viene imposta al fascio incidente. Questo risultato ci ha permesso di ottimizzare i parametri di costruzione della spirale realiz- zata in PMMA per applicazioni astronomiche. Abbiamo infatti assemblato il primo prototipo di un coronografo a vortici ottici, nel cui cammino ottico é stata inserita la spirale di fase realizzata in base ai parametri da noi definiti. I coronografi, in generale, sono strumenti progettati per bloccare la luce proveniente da una sorgente brillante in modo tale da poter osservare direttamente delle sorgenti piú deboli nelle vicinanze. Il coronografo a vortici ottici sfrutta la regione buia nella di- stribuzione d’intensitá di un vortice ottico per attenuare la luce di una sorgente luminosa, senza diminuire l’intensitá della sorgente secondaria. Abbiamo testato il nostro prototipo al telescopio ’Galileo’ 122cm di Asiago, attenuando l’in- tensitá di una componente del sistema stellare doppio Epsilon2 Lyrae di quasi un ordine di magnitudine. L’applicazione astronomica della spirale di fase ci ha spinto allo studio delle sua efficienza, ovvero del contrasto che si ottiene nella zona buia del vortice ottico, a diverse distanze angolari della sorgente secondaria rispetto alla singolaritá centrale della spirale. Simulazioni numeriche hanno mostrato che il coronografo a vortici ottici funziona anche al di sotto del limite di risoluzione di Rayleigh. La ricerca si é sviluppata fino alla formulazione di un nuovo metodo per determinare la distanza angolare tra due sorgenti distanti meno del criterio di Rayleigh. Il nuovo metodo sfrutta la distribuzione d’intensitá asimmetrica dei vortici ottici prodotti dalla sorgente secondaria che passa attraverso la spirale di fase, ma non in corrispondenza della singolaritá centrale. Poiché le equazioni di Maxwell sono valide su tutto lo spettro elettromagnetico, i vortici posso- no essere prodotti anche in diverse bande rispetto al visibile. Basandoci su questo fondamentale principio abbiamo studiato delle ottiche diffrattive per la produzione di vortici nel range del radio. Abbiamo costruito con polistirolo e alluminio una spirale di fase basandoci sui risultati trovati nel visibile ed abbiamo ottenuto la prima evidenza sperimentale di un vortice radio. La verifica speri- mentale della possibilitá di generare e sfruttare vortici radio ha spianato la strada all’esperimento successivo che é stato condotto nel campo della comunicazione radio. Abbiamo compiuto la prima trasmissione OAM in cui due segnali sono stati trasmessi con- temporaneamente e sulla stessa frequenza, su due canali radio codificati in due diversi stati di momento angolare orbitale. Questa nuova tecnica radio permette, in teoria, di codificare un infinito numero di canali in una singola banda centrata su una frequenza. I risultati dei nostri esperimenti nel dominio del radio aprono nuove prospettive nel mondo della comunicazione.
42
Wiklund, Henrik. "Numerical calculations of optical structures using FEM". Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7326.
Testo completoAbstract (sommario):
Complex surface structures in nature often have remarkable optical properties. By understanding the origin of these properties, such structures may be utilized in metamaterials, giving possibilities to create materials with new specific optical properties. To simplify the optical analysis of these naturally developed surface structures there is a need to assist data analysis and analytical calculations with numerical calculations.
In this work an application tool for numerical calculations of optical properties of surface structures, such as reflectances and ellipsometric angles, has been developed based on finite element methods (FEM). The data obtained from the application tool has been verified by comparison to analytical expressions in a thorough way, starting with reflection from the simplest of interfaces stepwise increasing the complexity of the surfaces.
The application tool were developed within the electromagnetic module of Comsol Multiphysics and used the script language to perform post-process calculations on the obtained electromagnetic fields. The data obtained from this application tool are given in such way that easily allows for comparison with data received from spectroscopic ellipsometry measurements.
43
McGuinness, Hayden James 1980. "The creation and frequency translation of single-photon states of light in optical fiber". Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/11259.
Testo completoAbstract (sommario):
xiii, 164 p. : ill. (some col.)We explore the frequency translation of single-photon states of light and the creation of photon pairs by four-wave mixing in optical fiber. Frequency translation refers to changing the central frequency of a field, while photon pair creation refers to the creation of two individual photons at the same time. We demonstrate these effects in third-order nonlinear optical fiber. While both phenomena have previously been shown by three-wave mixing in second-order nonlinear media, there are compelling reasons to develop these tasks in third-order media. Most importantly, frequency translation in third-order material allows for the practical implementation of both small and large frequency shifts, while second-order material only practically allows for large shifts. Photon creation in third-order media often permits more flexible phase-matching conditions, allowing for the creation of a wider variety of quantum states than is often possible in second-order media. In our theoretical study of photon pair creation, we focus on the spectral correlations of the photon pairs. We pay particular attention to the creation of quantum states of high purity, where the photons are not spectrally correlated with one another. High purity photons are a requisite resource for several different quantum information processing applications, such as linear-optical quantum computing. We find that states with high purity can be realized with a minimal amount of spectral filtering. Experimentally, we study photon frequency translation in photonic crystal fiber. The central wavelength of the input photons was translated from 683 nm to 659 nm. We perform second-order intensity correlation measurements on both channels to demonstrate their quantum nature. This resulted in values of 0.21 ± 0.02 and 0.19 ± 0.05 for the 683-nm and 659-nm channels, respectively, demonstrating that those fields were dominated by their single-photon component. The efficiency at which the process occurred was 29 percent. Theoretically, we develop a Green function formalism to describe the translation process and develop a computational model to calculate the solution to the governing equations. Also, in a related experiment, we demonstrate classical frequency translation from 851 nm to 641 nm, a record translation in both wavelength and frequency, at an efficiency of 0.2 percent in a birefringent fiber.
Committee in charge: Dr. Daniel Steck, Chair; Dr. Michael Raymer, Advisor; Dr. Steven van Enk, Inside Member; Dr. Raghuveer Parthasarathy, Inside Member; Dr. Andrew Marcus, Outside Member
44
Richmond, Eric William. "Birefringent single-arm fiber optic enthalpimeter for catalytic reaction monitoring". Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-07282008-135248/.
Testo completo
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Greaves, James David. "Numerical analysis of the outside vapor deposition process". Ohio : Ohio University, 1990. http://www.ohiolink.edu/etd/view.cgi?ohiou1183491109.
Testo completo
46
Wheelwright, Brian. "Freeform Solar Concentrating Optics". Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/577087.
Testo completoAbstract (sommario):
Notwithstanding several years of robust growth, solar energy still only accounts for<1% of total electrical generation in the US. Before solar energy can substantially replace fossil fuels subsidy-free at utility scale, further cost reductions and efficiency improvements are needed in complete generating systems. Flat panel silicon PV modules are by far the most dominant solar technology today, but have little room for improvement in efficiency and are limited by balance of system costs. Concentrated PV (CPV) is an alternate approach with long-term potential for much higher efficiency in sunny climates. In CPV modules, large area optics collect and concentrate direct sunlight onto small multi-junction cells with>40% conversion efficiency. Concentrated Solar Power (CSP) uses mirrors to concentrate sunlight onto thermally absorbing receivers, which generate electricity with convention thermal cycles. In this dissertation, four new optical approaches to CPV and CSP with potential for lower cost are analyzed. Common to each approach is the use of large square glass reflectors, which have very low areal cost (~$35/m^2) and field-proven reliability in the CSP industry. Chapter 2 describes a freeform toroidal lens array used to intercept the low concentration line focus of a parabolic trough to produce multiple high concentration foci (>800X) for multi-junction cells. In Chapter 3, three embodiments of dish mirrors and freeform lenslet arrays are explored, including an off-axis system. In each case, a dish mirror illuminates a freeform lenslet array, which divides sunlight equally to a sparse matrix of multi-junction cells. The off-axis optical system achieves +/-0.45° acceptance angle and averages 1215X geometric concentration over 400 multi-junction cells. Chapter 4 proposes a new architecture for CSP central receivers that achieves extremely high collection efficiency (>70%) with unconventional heliostat field tracking. In Chapter 5, the design and preliminary testing of a spectrum-splitting hybrid PV/thermal generator is discussed. This system has the advantage of 'drop-in' capability in existing CSP trough plants and allows for thermal storage, an important mitigation to the intermittency of the solar resource.
47
Chen, Yang. "Thermal Forming Process for Precision Freeform Optical Mirrors and Micro Glass Optics". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1267477993.
Testo completo
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Ruege, Alexander Charles. "Electro-Optic Ring Resonators in Integrated Optics For Miniature Electric Field Sensors". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322521235.
Testo completo
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Ireeta, Winston Tumps. "Aerial optical fibres in telecommunication systems : SOP and PMD monitoring, and tolerance of modulation formats". Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1478.
Testo completoAbstract (sommario):
The topic of this thesis is aerial optical fibres in telecommunication systems: state of polarization (SOP) and polarization mode dispersion (PMD) monitoring and tolerance of modulation formats. Errors in optical fibre telecommunication systems are introduced when these polarization effects (SOP and PMD) change. These changes are so intense especially in aerial optical fibres. Part of the backbone of South Africa’s national grid includes long distances of aerial optical fibre between transmission exchange stations. The work in this thesis can be divided into three parts which all deal with the major aspects of PMD in deployed aerial optical fibres: characterization, environmental effects plus other perturbations, and tolerance of different modulation formats. In our work, SOP and PMD field measurements revealed that they both fluctuate more rapidly in deployed aerial optical fibres especially on windy and hot days. The SOP and PMD changes in the aerial optical fibres showed a significant correlation with these environmental parameters. SOP and PMD are stochastic in nature due to changes in the properties of the optical fibres and its positions because of both intrinsic and extrinsic perturbations. In our work, with only 184 PMD values measured and obtained by use of the FTB-5700 single-ended dispersion analyzer, the predicted theoretical Gaussian fit was obtained with a mean of 0.47 ps and standard deviation of 0.08 ps. This small standard deviation was justification for its robustness and accuracy. The statistical distributions for first-order polarization mode dispersion (FO-PMD) and second-order polarization mode dispersion (SO-PMD) for the first time were experimentally confirmed when measured using the FTB-5700 single-ended dispersion analyzer instrument for deployed aerial optical fibres. We were also able to determine the time scale over which to compensate FO-PMD in deployed aerial fibres using the directional time drift autocorrelation function method. It is slightly higher than 390 s for SOP measurements made on a particular windy and hot day. This is due to the fact that the changes of the PMD vector are known to be slower than the SOP changes. vi We also investigated the theoretical statistical distribution that corresponds to output SOP variations. The SOP variations can either be with wavelength (for buried fibre) or with time (for aerial fibre). Our results showed that the statistics of the relative SOP changes approached the distribution proposed by Foschini et al. (2000). Advanced optical modulation formats have become a key ingredient in the design of modern state-of-the-art wavelength-division-multiplexed (WDM) optical transmission systems. In our work, we investigated which of these advanced modulation formats is best suited for the South African network especially on systems that have links of aerial optical fibres. Keywords: aerial optical fibre, polarization mode dispersion (PMD), principal states of polarization (PSP), state of polarization (SOP), first-order PMD, second-order PMD.
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Kuhlmey, Boris T. "Theoretical and numerical investigation of the physics of microstructured optical fibres". Connect to full text, 2004. http://setis.library.usyd.edu.au/adt/public_html/adt-NU/public/adt-NU20040715.171105.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--School of Physics, Faculty of Science, University of Sydney, 2004. (In conjunction with: Université de Droit, d'Économie et des Sciences d'Aix-Marseille (Aix Marseille III)).Bibliography: leaves 196-204.