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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Construction, Deployment and Data Analysis of the E and B EXperiment: A Cosmic Microwave Background Polarimeter

Didier-Scapel, Joy Maria Elise January 2016 (has links)
The E and B EXperiment (EBEX) is a pointed balloon-borne telescope designed to measure the polarization of the cosmic microwave background (CMB) as well as that from Galactic dust. The instrument is equipped with a 1.5 meter aperture Gregorian-Dragone telescope, providing an 8' beam at three frequency bands centered on 150, 250 and 410 GHz. The telescope is designed to measure or place an upper limit on inflationary B-mode signals and to probe B-modes originating from gravitationnal lensing of the CMB. The higher EBEX frequencies are designed to enable the measurement and removal of polarized Galactic dust foregrounds which currently limit the measurement of inflationary B-modes. Polarimetry is achieved by rotating an achromatic half-wave plate (HWP) on a superconducting magnetic bearing. In January 2013, EBEX completed 11 days of observations in a flight over Antarctica covering 6,000 square degrees of the southern sky. This marks the first time that kilo-pixel TES bolometer arrays have made science observations on a balloon-borne platform. In this thesis we report on the construction, deployment and data analysis of EBEX. We review the development of the pointing sensors and software used for real-time attitude determination and control, including pre-flight testing and calibration. We then report on the 2013 long duration flight (LD2013) and review all the major stages of the analysis pipeline used to transform the ~1 TB of raw data into polarized sky maps. We review "LEAP", the software framework developed to support the analysis pipeline. We discuss in detail the novel program developed to reconstruct the attitude post-flight and estimate the effect of attitude errors on measured B-mode signals. We describe the bolometer time-stream cleaning procedure including removing the HWP-synchronous signal, and we detail the map making procedure. Finally we present a novel method to measure and subtract instrumental polarization, after which we show Galaxy and CMB maps.
52

Experimental studies of spatial soliton, polarization rotation and hall effect in photorefractive crystal. / 有關光折變晶體中空間孤子、偏振轉動以及霍爾效應的研究 / Experimental studies of spatial soliton, polarization rotation and hall effect in photorefractive crystal. / You guan guang zhe bian jing ti zhong kong jian gu zi, pian zhen zhuan dong yi ji Huoer xiao ying de yan jiu

January 2005 (has links)
Yuen Chi Yan = 有關光折變晶體中空間孤子、偏振轉動以及霍爾效應的研究 / 阮志仁. / Thesis submitted in: July 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 81-82). / Text in English; abstracts in English and Chinese. / Yuen Chi Yan = You guan guang zhe bian jing ti zhong kong jian gu zi, pian zhen zhuan dong yi ji Huoer xiao ying de yan jiu / Ruan Zhiren. / Acknowledgments --- p.i / Abstract --- p.ii / Table of Contents --- p.v / Chapter Chapter 1 --- Photorefractive Spatial Soliton --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Bright Spatial Soliton --- p.3 / Chapter 1.2.1 --- Experiment --- p.4 / Chapter 1.2.2 --- Results and Discussion --- p.6 / Chapter 1.2.2.1 --- Expansion --- p.6 / Chapter 1.2.2.2 --- Contraction --- p.10 / Chapter 1.3 --- Dark Spatial Soliton --- p.15 / Chapter 1.3.1 --- Experiment --- p.15 / Chapter 1.3.2 --- Results and Discussion --- p.20 / Chapter Chapter 2 --- Polarization Rotation --- p.23 / Chapter 2.1 --- Introduction --- p.23 / Chapter 2.2 --- Experiment --- p.24 / Chapter 2.3 --- Results and Discussion --- p.30 / Chapter 2.3.1 --- Effect of varying pump beam power --- p.30 / Chapter 2.3.2 --- Effect of different polarizations of signal beam --- p.41 / Chapter 2.3.3 --- Effect of signal beam size --- p.43 / Chapter 2.3.4 --- Effect of applied E-field --- p.46 / Chapter 2.3.5 --- Effect of signal beam and pump beam separation and perpendicularly --- p.52 / Chapter 2.3.6 --- Investigation of Δne using interferometer --- p.60 / Chapter 2.3.7 --- Computer Simulation --- p.69 / Chapter Chapter 3 --- Hall Effect --- p.72 / Chapter 3.1 --- Introduction --- p.72 / Chapter 3.2 --- Experiment --- p.75 / Chapter 3.3 --- Results and Discussion --- p.76 / Conclusion and Possible Further Works --- p.79 / References --- p.81
53

Silicon waveguides and methods to address their polarization sensitivity =: 以硅為基的光波導及其偏振敏度解決方案. / 以硅為基的光波導及其偏振敏度解決方案 / Silicon waveguides and methods to address their polarization sensitivity =: Yi gui wei ji de guang bo dao ji qi pian zhen min du jie jue fang an. / Yi gui wei ji de guang bo dao ji qi pian zhen min du jie jue fang an

January 2003 (has links)
Chan Po Shan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 79). / Text in English; abstracts in English and Chinese. / Chan Po Shan. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Application of Optical Waveguides --- p.1 / Chapter 1.2 --- Planar Waveguide Characterizations --- p.2 / Chapter 1.3 --- Silicon-On-Insulator Rib Waveguides --- p.3 / Chapter 1.4 --- Polarization compensation schemes --- p.4 / Chapter 1.5 --- Objectives --- p.6 / Chapter 2 --- Silicon-On-Insuiator Rib Waveguides --- p.9 / Chapter 2.1 --- Properties of Silicon Waveguides --- p.9 / Chapter 2.2 --- Single Mode Rib Waveguides Simulations --- p.11 / Chapter 2.3 --- Special design optimisations --- p.14 / Chapter 2.4 --- Fabrications and Results --- p.16 / Chapter 3 --- Polarization Characteristics of SOI Rib Waveguides --- p.20 / Chapter 3.1 --- Properties of silicon and effect of rib structure --- p.20 / Chapter 3.2 --- Polarization affected by Form Birefringence --- p.21 / Chapter 3.3 --- Case Study: Arrayed Waveguide Grating --- p.23 / Chapter 3.4 --- Possibility of polarization Compensation in planar waveguides --- p.26 / Chapter 4 --- Fixed Polarization Compensation Techniques --- p.30 / Chapter 4.1 --- Theoretical analysis of slant rib waveguides on polarization --- p.30 / Chapter 4.2 --- Focused Ion Beam Trimming of SOI waveguides --- p.31 / Chapter 4.3 --- Possible applications --- p.36 / Chapter 5 --- Tuneable Polarization Compensation Techniques --- p.41 / Chapter 5.1 --- stress on rib waveguide for polarization compensation --- p.41 / Chapter 5.2 --- Magnetostriction and Magnetostrictive Materials --- p.42 / Chapter 5.3 --- Sputtering of soft magnetic layer on SOI rib waveguides --- p.46 / Chapter 5.4 --- Test results and Analysis --- p.47 / Chapter 6 --- Advanced SOI Devices --- p.55 / Chapter 6.1 --- Unique planar optoelectronics devices --- p.55 / Chapter 6.2 --- Simulation and Fabrications --- p.57 / Chapter 6.3 --- Test Results and Discussion --- p.58 / Chapter 7 --- Conclusion --- p.62 / Chapter 7.1 --- Summary --- p.62 / Chapter 7.2 --- Future work --- p.63 / Appendices / Chapter A1 --- Effective Index Method --- p.66 / Chapter A2 --- Beam Propagation Method --- p.70 / Chapter A3 --- SOI Rib Waveguide Fabrication --- p.72 / Chapter A4 --- Focused Ion Beam --- p.74 / Chapter A5 --- Polarization Optics --- p.76 / List of Publications --- p.79
54

Disentanglement dynamics of photons in noisy environment. / 光子在噪聲環境中的解糾纏 / Disentanglement dynamics of photons in noisy environment. / Guang zi zai zao sheng huan jing zhong de jie jiu chan

January 2008 (has links)
Poon, Sin Yau = 光子在噪聲環境中的解糾纏 / 潘善柔. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 101-110). / Abstracts in English and Chinese. / Poon, Sin Yau = Guang zi zai zao sheng huan jing zhong de jie jiu chan / Pan Shanrou. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Review on entanglement theory --- p.4 / Chapter 2.1 --- Pure state entanglement --- p.4 / Chapter 2.2 --- Mixed state entanglement --- p.7 / Chapter 2.3 --- Positive partial transposition (PPT) criterion --- p.9 / Chapter 2.4 --- Negativity of pTA --- p.9 / Chapter 2.4.1 --- Basic properties --- p.10 / Chapter 2.4.2 --- Comparison with concurrence --- p.11 / Chapter 2.5 --- Entanglement witness --- p.12 / Chapter 2.6 --- Inseparability criterion based on uncertainty relations --- p.13 / Chapter 2.7 --- Limitations of the PPT criterion --- p.14 / Chapter 2.8 --- Other manifestations of entanglement --- p.16 / Chapter 2.8.1 --- Non-classicality by negative P-representation --- p.16 / Chapter 2.8.2 --- Non-locality by violation of Bell´ةs inequality --- p.17 / Chapter 3 --- Quantum decoherence: General considerations for open systems --- p.22 / Chapter 3.1 --- A master equation approach --- p.22 / Chapter 3.1.1 --- Master equation in Markovian channels --- p.25 / Chapter 3.2 --- Negativity as a monotone in Markovian systems --- p.26 / Chapter 3.3 --- Finite time disentanglement --- p.29 / Chapter 3.4 --- Non-classicality of harmonic oscillating systems in finite temperature baths --- p.32 / Chapter 4 --- Disentanglement dynamics of two-mode Gaussian states --- p.36 / Chapter 4.1 --- Two-mode Gaussian states: General descriptions --- p.36 / Chapter 4.1.1 --- Covariance matrices and symplectic eigenvalues --- p.37 / Chapter 4.1.2 --- Squeezed states as a source of entanglement --- p.39 / Chapter 4.2 --- Eigenvalues and eigenvectors of pTA --- p.41 / Chapter 4.3 --- Physical interpretation of negativity --- p.43 / Chapter 4.4 --- Disentanglement of two-mode squeezed states in damping and amplifying environment --- p.47 / Chapter 4.4.1 --- Block structures of pTA in Fock space --- p.47 / Chapter 4.4.2 --- Analytic solution of p in position space --- p.49 / Chapter 4.4.3 --- Evolution of eigenvalues and eigenvectors of pTA --- p.51 / Chapter 4.4.4 --- Robust structure of entanglement witness --- p.56 / Chapter 4.5 --- Beam splitter as a model for thermal damping of initial Gaussian states --- p.59 / Chapter 4.6 --- Evolution of entanglement of a damped parametric oscillator --- p.63 / Chapter 4.6.1 --- Eigenvalues and Eigenvectors of pTA --- p.64 / Chapter 4.6.2 --- Negativity and sub-negativity --- p.66 / Chapter 4.7 --- Dissipation in baths with both amplitude and phase damping --- p.68 / Chapter 4.8 --- Loss of nonlocality: An optimized Bell's inequality approach --- p.69 / Chapter 5 --- Disentanglement via polarization mode dispersion --- p.73 / Chapter 5.1 --- Review on polarization mode dispersion --- p.73 / Chapter 5.2 --- A model for stochastic polarization mode dispersion --- p.75 / Chapter 5.3 --- General description of two-photon states --- p.78 / Chapter 5.4 --- Disentanglement of two-photon states in separate fibers --- p.81 / Chapter 5.4.1 --- Polarization negativity and frequency negativity --- p.83 / Chapter 5.4.2 --- Polarization disentanglement --- p.84 / Chapter 5.4.3 --- Frequency disentanglement --- p.85 / Chapter 5.5 --- Disentanglement of two-photon states in a common fiber --- p.86 / Chapter 5.5.1 --- Polarization disentanglement of the singlet state --- p.90 / Chapter 5.5.2 --- Frequency entanglement of the singlet state --- p.91 / Chapter 5.6 --- Non-Markovian channels --- p.92 / Chapter 6 --- Conclusion --- p.99 / Bibliography --- p.101 / Chapter A --- CHSH Inequality for bipartite two level systems --- p.111 / Chapter B --- Transformation from general two-mode Gaussian to double Gaussian product --- p.113 / Chapter C --- Time evolution of general real symmetric two-mode Gaussian density operator --- p.116 / Chapter D --- Time evolution of a damped parametric oscillator --- p.119 / Chapter E --- Optimal Bell values for a damped TMSV in pseudo-spin formalism --- p.123 / Chapter F --- Derivation of master equation for two-photon states --- p.125 / Chapter G --- Solution of master equation for two-photon states --- p.127 / Chapter G.1 --- Evolution of two-photon states in separate fibers --- p.127 / Chapter G.2 --- Evolution of two-photon state in a common fiber --- p.129
55

Novel thin film optical modulator/tunable retarder

Keeling, David. January 2007 (has links)
Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007. / Committee Chair: A. Rahman Zaghloul ; Committee Members: W. Russell Callen and Doug Yoder. Part of the SMARTech Electronic Thesis and Dissertation Collection.
56

Depolarization effects at 3 GHz due to precipitation

Humphries, Robert Gordon January 1974 (has links)
No description available.
57

Polarization modulation and splicing techniques for stressed birefringent fiber /

Robinson, Risa J. January 1995 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 1995. / Typescript. Bibliography: leaves 107-114.
58

A inclusão dos efeitos de temperatura na função resposta dielétrica do modelo de Dissado-Hill e seu potencial para implicações em materiais de interesse para eletrônica

Cambruzzi Filho, Onerio 11 June 2014 (has links)
Nesta dissertação apresentamos os conceitos e ferramentas necessárias para análise do comportamento da função resposta dielétrica de meios dielétricos, levando em conta efeitos da temperatura. Nos primeiros capítulos apresentamos uma breve revisão da literatura especializada, expondo alguns modelos que foram propostos para a descrição da função resposta dielétrica. A seguir apresentamos alguns modelos teóricos encontrados na literatura que incorporam efeitos da temperatura à resposta dielétrica. Considerando o modelo proposto por Dissado-Hill, mostramos que os efeitos da temperatura podem ser incorporados aos parâmetros (m) e (n) que caracterizam o modelo. / In this work we present the concepts and tools required to analyze the behavior of the dielectric response function of dielectric media, taking into account the effects of temperature. In the early chapters, we present a brief review of the literature, exposing some models that have been proposed to describe the dielectric response function, then we include the presentation of some models found in the literature that incorporate the effects of temperature to dielectric response for some materials. In order to include the effects of temperature in the dielectric response of interest materials for electronic (such as ceramics), we assuming the Dissado-Hill model, and show that the effects of temperature may be included in the parameters (m) and (n) that characterizing the model.
59

A inclusão dos efeitos de temperatura na função resposta dielétrica do modelo de Dissado-Hill e seu potencial para implicações em materiais de interesse para eletrônica

Cambruzzi Filho, Onerio 11 June 2014 (has links)
Nesta dissertação apresentamos os conceitos e ferramentas necessárias para análise do comportamento da função resposta dielétrica de meios dielétricos, levando em conta efeitos da temperatura. Nos primeiros capítulos apresentamos uma breve revisão da literatura especializada, expondo alguns modelos que foram propostos para a descrição da função resposta dielétrica. A seguir apresentamos alguns modelos teóricos encontrados na literatura que incorporam efeitos da temperatura à resposta dielétrica. Considerando o modelo proposto por Dissado-Hill, mostramos que os efeitos da temperatura podem ser incorporados aos parâmetros (m) e (n) que caracterizam o modelo. / In this work we present the concepts and tools required to analyze the behavior of the dielectric response function of dielectric media, taking into account the effects of temperature. In the early chapters, we present a brief review of the literature, exposing some models that have been proposed to describe the dielectric response function, then we include the presentation of some models found in the literature that incorporate the effects of temperature to dielectric response for some materials. In order to include the effects of temperature in the dielectric response of interest materials for electronic (such as ceramics), we assuming the Dissado-Hill model, and show that the effects of temperature may be included in the parameters (m) and (n) that characterizing the model.
60

A comparative polarimetric study of the 43 GHz and 86 GHz SiO masers toward the supergiant star VY CMa

Richter, Laura January 2012 (has links)
The aim of this thesis is to perform observational tests of SiO maser polarisation and excitation models, using component-level comparisons of multiple SiO maser transitions in the 43 GHz and 86 GHz bands at milliarcsecond resolution. These observations reqwre very long baseline interferometric imaging with very accurate polarimetric calibration. The supergiant star VY CMa was chosen as the object of this study due to its high SiO maser luminosity, many detected SiO maser lines, and intrinsic scientific interest. Two epochs of full-polarisation VLBA observations of VY CMa were performed. The Epoch 2 observations were reduced using several new data reduction methods developed as part of this work, and designed specifically to improve the accuracy of circular polarisation calibration of spectral-line VLBI observations at millimetre wavelengths. The accuracy is estimated to be better than 1% using these methods. The Epoch 2 images show a concentration of v= l and v=2 J= 1-0 SiO masers to the east and northeast of the assumed stellar position. The v=l J=2-1 masers were more evenly distributed around the star, with a notable lack of emission in the northeast. There is appreciable spatial overlap between these three lines. The nature of the overlap is generally consistent with the predictions of hydrodynamical circumstellar SiO maser simulations. Where the v=l J = 1-0 and J =2-1 features overlap, the v=l J = 2-1 emission is usually considerably weaker. This is not predicted by current hydrodynamical models, but can be explained in the context of collisional pumping in a low density environment. Six observational tests of weak-splitting maser polarisation models were performed, including intercomparisons of linear polarisation in the v=l J=1-0 and J=2-1lines, linear polarisation versus saturation level, linear polarisation versus distance from the star, circular polarisation in the v= l J = 1-0 and J=2-1 lines, circular versus linear polarisation and modeling of ~ 900 electric-vector position angle rotations. The polarisation model tests generally do not support non-Zeeman circular polarisation mechanisms. For the linear polarisation tests, the results are more consistent with models that predict similar linear polarisation across transitions. The scientific importance of these tests is described in detail and avenues for future work are described.

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