Abstract not available.

[Truncated abstract] The research described in this thesis investigated optical spring interactions and instabilities in a macroscopic opto-mechanical resonator. The thesis describes an experiment designed to model an optical spring `tranquiliser’ cavity which has been proposed to suppress the predicted parametric instabilities in the next generation of interferometric gravitational wave detectors. In a series of experiments, the optical spring effect was observed in macroscopic optical cavities through measured changes in mechanical stiffness, and measured changes in mechanical loss. The optical spring effect was further characterised through investigation of its dependent parameters. Two pairs of identical, low optical loss mirrors were bonded to a mechanical structure using a novel low mechanical loss technique, forming an opto-mechanical composite resonator. The technique uses the naturally occurring resin Yacca gum as a bonding agent. This resulted in the formation of two optical cavities with a length of l = 0.100±0.001m, only one of which was used in experiments. Using finite element modelling, the resonator?s two lowest modes, with frequencies of fm1 = 722.8Hz and fm2 = 747.9Hz, and an effective mass 0.0323±0.0001kg, were found to be subject to the optical spring effect. ... The instabilities are expected to have a parametric gain factor of up to 100 in the frequency range of 15-120kHz. Therefore, if optical spring damping can be made large enough to reduce the Q-factor of the Advanced LIGO test-masses by a factor of 100, all parametric instabilities should be eliminated. For a simple servo loop and an optical cavity with the practically achievable finesse of F = 30,000, a tranquiliser cavity length of 1.3cm was found to produce optimum enhanced damping. This configuration only requires 1.47W of input power, resulting in an intra-cavity power of 5.72kW. The cavity mirrors were assumed to have optical coatings with a damage threshold of 1MW/cm2, which limited the spot size to a minimum area of 0.572mm2, or a radial beam waist of w = 0.427mm. This nearly flat-flat cavity has a stability g-factor of 0.9997. Even given these technical challenges, suppression of the parametric instabilities predicted to occur in the next generation of interferometric detectors is possible to achieve practically using enhanced optical spring damping. A possible design for such a tranquiliser cavity is also suggested.

Thesis (M.App.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 85-91). Also available in electronic format on the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 67-68). Also available via the Internet.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed June 26, 2009). PDF text: x, 153 p. : ill. (some col.) ; 9 Mb. UMI publication number: AAT 3350442. Includes bibliographical references. Also available in microfilm and microfiche formats.

Paper discusses the expected uncertainty of orbital parameters of binary stars as measured by the space-based gravitational wave observatory LISA (Laser Interferometer Space Antenna) and how the inclusion of spin in the model of the binary stars affects the uncertainty. The uncertainties are found by calculating the received gravitational wave from a binary pair and then performing a linear least-squares parameter estimation. The case of a 1500 solar mass black hole that is 20 years from coalescing with a 1000 solar mass black hole--both of which are 50 x 10^6 light years away--is analyzed, and the results show that the inclusion of spin has a negligible effect upon the angular resolution of LISA but can increase the accuracy in mass and distance measurements by factors of 15 and 65, respectively.

Made available in DSpace on 2014-06-11T19:35:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-06-22Bitstream added on 2014-06-13T21:08:04Z : No. of bitstreams: 1 shimizu_fm_dr_bauru.pdf: 1060296 bytes, checksum: 63745c957542a90554b00f3723c1c813 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Foi desenvolvida uma montagem experimental para estudar o processo de polarização fotoassistida (PAP) de filmes finos poliméricos utilizando um interferômetro de Mach-Zehnder (IMZ). Ela permite determinar a atividade eletro-óptica do filme durante e após o processo de polarização. Um cristal de KH2PO4 (KDP) e o filme guest-host do polímero acrílico poli(metacrilato de metila), PMMA, dopado com o corante vermelho disperso 1, DR1, mostraram o bom funcionamento do sistema de medição IMZ/PAP. Dois azopolímeros acrílicos, o poli(metacrilato de vermelho disperso 1), PMDR1, e o poli(metacrilato de metila)-co-(metacrilato de vermelho disperso 1), PMMcoMDR1, foram estudados variando-se a tensão dc de polarização e a intensidade da luz de excitação. Os dados experimentais obtidos foram ajustados por equações fenomenológicas de Sekkat e KWW para obtenção dos tempos característicos de cada processo durante e após a polarização do filme. O valor máximo de coeficiente eletro-óptico de ~20pm/V foi obtido para o filme do polímero acrílico de PMDR1, enquanto que para os filmes de PMMA/DR1 e PMMcoMDR1 os valores foram de 0,5 e 1,6 pm/V / We developed an experimental setup aiming to study the photoassisted poling (PAP) of polymeric films using a Mach-Zehnder interferometer (MZI). Is allows measuring the electric optic coefficient during and after the photoassisted poling process. The proper operation the IMZ/PAP measurement system was demonstrated using a KH2PO4 (KDP) crystal and poly(methyl methacrylate), PMMA, doped with the dye disperse red 1, DR1, guest-host films. Two acrylic azopolymers, poly(methacrylate disperse red 1), PMDR1, and poly(methyl methacrylate)-co-(methacrylate disperse red 1), PMMcoMDR1 were studied under different dc voltage poling and light excitation intensity. The experimental data obtained were fitted by Sekkat and KWW equations to give the characteristics time of each poling process and its decays. The maximum electro-optical coefficient of ~20 pm/V were obtained with the PMDRI acrylic polymer film while for PMMA/DR1 and PMMcoMDR1 the values were 0.5 and 1.6 pm/V

This thesis is concerned with the guiding of cold atoms using optical forces, which is of great importance in the field of atom optics. Atomic beams can be used for precision sensor equipment, building nano-scale structures, construction of quantum computers and to further the understanding of the properties of atoms. Atoms are guided along light beams using the dipole force; there are two regimes under which this force works. Typically red-detuned guides are used (atoms are attracted towards the light) such guides, however, require large detuning and high powers. In this thesis we investigate the use of blue-detuned (atoms are repelled from the light) hollow light beams of moderate power (a few hundred mW) and confine atoms in the dark centre of the beams. Several magneto-optical traps (MOTs) have been constructed to exploit different guiding geometries. Hollow beams have been generated using a variety of methods; in particular the use of a computer controlled spatial light modulator (SLM) has provided great versatility and simplicity to the experimental arrangements. First, experiments were performed with a low-velocity intense source (LVIS) of atoms. A co-linear LG beam significantly enhances the observed flux, however, considerable difficulties are encountered loading atoms into oblique guides. Imaging a hole in the walls of the light tube was used to improve the loading efficiency. Second, guiding a free-falling atom cloud is performed using a non-diffracting Bessel beam. It is found that while the potential of the Bessel beam is steeper than equivalent LG beams the power distribution across the beam severely limits its usefulness. The next study investigated higher-order LG guide beams generated with an SLM. High order modes have a narrower profile so confine the atoms with less interaction with the guide beam, leading to a more natural guide (as opposed to a pushing force). Finally the SLM was used to create non-trivial beam shapes for beam splitters and interferometers.

Orientador: José Alberto Giacometti / Banca: Sandro Márcio Lima / Banca: Fernando Fuzinatto Dall'Agnol / Banca: Victor Ciro Solano Reynoso / Banca: Clarissa de Almeida Olivati / O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi / Resumo: Foi desenvolvida uma montagem experimental para estudar o processo de polarização fotoassistida (PAP) de filmes finos poliméricos utilizando um interferômetro de Mach-Zehnder (IMZ). Ela permite determinar a atividade eletro-óptica do filme durante e após o processo de polarização. Um cristal de KH2PO4 (KDP) e o filme guest-host do polímero acrílico poli(metacrilato de metila), PMMA, dopado com o corante vermelho disperso 1, DR1, mostraram o bom funcionamento do sistema de medição IMZ/PAP. Dois azopolímeros acrílicos, o poli(metacrilato de vermelho disperso 1), PMDR1, e o poli(metacrilato de metila)-co-(metacrilato de vermelho disperso 1), PMMcoMDR1, foram estudados variando-se a tensão dc de polarização e a intensidade da luz de excitação. Os dados experimentais obtidos foram ajustados por equações fenomenológicas de Sekkat e KWW para obtenção dos tempos característicos de cada processo durante e após a polarização do filme. O valor máximo de coeficiente eletro-óptico de ~20pm/V foi obtido para o filme do polímero acrílico de PMDR1, enquanto que para os filmes de PMMA/DR1 e PMMcoMDR1 os valores foram de 0,5 e 1,6 pm/V / Abstract: We developed an experimental setup aiming to study the photoassisted poling (PAP) of polymeric films using a Mach-Zehnder interferometer (MZI). Is allows measuring the electric optic coefficient during and after the photoassisted poling process. The proper operation the IMZ/PAP measurement system was demonstrated using a KH2PO4 (KDP) crystal and poly(methyl methacrylate), PMMA, doped with the dye disperse red 1, DR1, guest-host films. Two acrylic azopolymers, poly(methacrylate disperse red 1), PMDR1, and poly(methyl methacrylate)-co-(methacrylate disperse red 1), PMMcoMDR1 were studied under different dc voltage poling and light excitation intensity. The experimental data obtained were fitted by Sekkat and KWW equations to give the characteristics time of each poling process and its decays. The maximum electro-optical coefficient of ~20 pm/V were obtained with the PMDRI acrylic polymer film while for PMMA/DR1 and PMMcoMDR1 the values were 0.5 and 1.6 pm/V / Doutor

Longtemps cantonnées au visible et au proche IR, des nanostructures résonantes sont à présent réalisées dans l’IR, notamment en vue d'applications spectroscopiques. Pour étudier la réponse de ces nanostructures des moyens de caractérisation spécifiques doivent être mise en œuvre. Nous considérons la réponse IR de nano-structures et développons des outils à même de les caractériser. Nous nous sommes intéressés à des échantillons pouvant présenter des modes localisés de surface associés à des Plasmons Polaritons au sein de semiconducteurs fortement dopés ou des Phonons Polaritons dans des matériaux semiconducteurs polaires comme SiC. Cette étude a été menée d’abord en champ lointain (Spectroscopie à Transformée de Fourier et analyse Kramers-Kronig) pour étudier la réponse collective des nanostructures. Nous montrons que la fonction diélectrique de l’échantillon structuré peut être représentée par un oscillateur de Lorentz amortit modifié. Une permittivité effective est aussi déterminée par l’emploi de matrices de transfert pour rendre compte de la réflectivité complexe. L’étude en champ proche permet ensuite d’obtenir une réponse individuelle des structures. Nous développons ici une méthode d’extraction novatrice de l’amplitude et de la phase du signal avec un rapport signal à bruit optimum. Après avoir théoriquement et expérimentalement démontré la pertinence de l’approche, la signature de SPP localisés a pu être observée par des cartographies de champ complexe en fonction de la longueur d’onde. Les images obtenues sont confrontées à des simulations électromagnétiques et discutées / We studied the response of a nano-structured material to an IR electromagnetic excitation. For a given geometry, this response is dictated by the dielectric function to which phonons and free carriers contribute. In case of defect-free semiconductors the phonon response is the dominant term; however when we consider doped semi-conductors the plasmon response plays a major role. In both case, the permittivity functions can be negative with small losses which permits a resonant coupling between the surface modes and the electromagnetic excitation. Our work focuses on the development of experimental tools to analyze both SPP and SPhP. This study was conducted in the far-field regime to see a collective response and in the near-field regime to study nano-structures individually. In far-field, the experimental spectroscopic response of the material was conducted by Fourier Transform Infrared Reflectivity and Kramers-Kronig analysis. Quantitative information on the dielectric function was extracted using a modified Lorentz damped oscillator to fit the reflectivity. An effective permittivity is also retrieved using a transfer matrix method. The near-field study was done in a two-step procedure. The first step was the development of an innovative detection technique with optimum signal to noise ratio. The second step was the implementation of this technique to NSOM after proving its success. LSPP were detected using the developed NSOM. A spectroscopic study was performed as well. Experimental results were compared to theoretical ones obtained with electromagnetic simulations