Includes bibliographical references. Electronic publication; full text available in PDF format; abstract in HTML format. Investigates the behaviour of the intensity noise in a multimode Nd:YAG laser. The collective modes of oscillation are excited by broadband ambient noise. Because the phase of the excitation is unknown, a cross spectral technique to measure the antiphase dynamics directly and form a picture of the intensity noise interference for two to five mode operation is developed. For three mode operation, the contributions of the longitudinal modes to collective modes is measured. Electronic reproduction.[Australia] :Australian Digital Theses Program,2001. ix, 163 leaves : ill., charts ; 30 cm.

Bibliography: leaves 154-156. / 156 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis describes the construction of a low-power end pumped Nd:YAG laser and the subsequent theoretical and experimental investigation of the antiphase dynamics exhibited by the laser. The end pumped laser was modelled by extending the classical model of Tang Statz deMars to non-uniform pump along the active medium. The anomalous threshold behaviour of the laser, where modes with lower gain can supass modes with higher gain as the pump power increases, was accounted for. The antiphase dynamics were explored by modulating the pump power and measuring the transfer functions from this input to various outputs. The laser's response to various sources of noise was also studied. / Thesis (Ph.D.)--University of Adelaide, School of Chemistry and Physics, Discipline of Physics and Mathematical Physics, 2003?

The topic of this thesis is solar pump Nd-doped double-clad fiber laser, the main characteristic of this research is we use nature and low pollution source pump unique laser gain medium. By using Neodymium-doped double-clad fiber in form of waveguide structure to replace Neodymium-doped glass, Neodymium-doped yttrium aluminum garnet crystals that have large cross-section area of the volume in the past¡F natural sunlight is used as pumped source in instead of diode laser, pulsed Xenon lamp, Krypton arc lamp¡Ketc. In order to reduce the use of electric power source and decrease the pollution . By using Solar concentration system, we focus average sunlight power density (800W/m2) to very high power density. In application, If lasers are needed in remote locations where sunlight is abundant and other forms of energy sources are scarce, this kind of solar energy usage is not a bad idea.

This study focuses on the design, fabrication, test and application of in-plane rotary electromagnetic micro-generator to obtain a high power output. The micro-generator comprises multilayer planar low temperature co-fired ceramics (LTCC) Ag micro-coil and multipole hard magnet of Nd/Fe/B. Finite element simulations have been carried out to observe electromagnetic information. The study also establishes analytical solutions for the micro-generator to predict the induced voltage. Three different configurations of planar micro-coils investigated, which are sector-shaped, circle-shaped, and square-shaped micro-coils. A prototype of the micro-generator is as small as 9¡Ñ9¡Ñ1 mm3 in volume size. The experimental results show that the micro-generator with sector-shaped micro-coil has the highest power output of 1.89 mW, and the effective value of the induced voltage of 205.7 mV at 13,325 rpm is achieved. In application, this study designed and fabricated a planar rotary electromagnetic energy harvester with a low rotary speed for use in bicycle dynamos. Finite element analysis and the Taguchi method were used to design this dynamo system. LTCC technology was applied to fabricate Ag planar multilayer coils with 20 layers. A 28-pole magnet Nd/Fe/B with an outer diameter of 50 mm and a thickness of 2 mm was also sintered and magnetized. This harvester system was approximately 50¡Ñ50¡Ñ3 mm3 in volume. The experimentally induced voltages for 20-layer coils were 1.539 V at the rotary speeds of 300 rpm. The power output was 0.788 mW with an external resistance load of 740 £[, and the efficiency was 26.62%. This harvester is capable of powering a minimum of 200 light emitted diodes (LEDs) (forward voltage (VF) <2.2 V and 20 mA) using a rotary speed of 250 rpm, and can be used for bicycle dynamo lighting.

On étudie la théorie et l'application pour plusieurs méthodes dans le domaine de l'estimation de la puissance spectrale. Dans le cas 1D, les deux approches de Levinson et Burg sont exposées dans le même contexte théorique et numérique. Dans le cas 2D, et plus généralement le cas ND, de nouvelles méthodes sont proposées pour l'estimation de la puissance spectrale. Ces méthodes conduisent à des extensions répondant à un critère de positivité et d'une maximisation d'une entropie adaptée à la puissance spectrale : la matrice de corrélation ND doit être définie positive et doit vérifier un critère de maximum d'entropie. Aussi, les systèmes de corrélation ND Toeplitz sont exposés dans le contexte des coefficients de réflexion généralisés pour le cas bloc Toeplitz, et le cas Toeplitz bloc Toeplitz. Dans les deux cas, on propose des nouveaux algorithmes pour la solution du système linéaire autorégressif. La structure ND Toeplitz de la matrice de corrélation est étudiée sous deux conditions. La première est que le support d'extension positive est infini avec une propriété de « matching » approximative. La deuxième est l'extension positive avec une propriété de maximum d'entropie. Suivant la deuxième condition, on formalise une théorie de positivité fondamentale, qui établit la correspondance entre un groupe minimal des coefficients de réflexion généralisés et la matrice de corrélation ND avec le même degré de liberté.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xi, 121 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 106-107).

The SNO+ experiment will be the SNO detector filled with a neodymium-loaded liquid scintillator instead of heavy water. SNO+ will be used to detect neutrinos of much lower energy. Also, SNO+ will conduct a search for neutrinoless double beta decay with Nd-150. The Nd-loaded scintillator in SNO+ will be made from linear alkylbenzene (LAB). Both the LAB solvent and the Nd loading are new developments. The optical properties of this scintillator and information about radioactive backgrounds should be studied. A calibration source known as the scintillator bucket was deployed in the water-filled SNO detector in order to study some optical properties of Nd-loaded scintillator, raw LAB scintillator and distilled LAB scintillator. Using a neutron source attached to the bucket to produce events with known energy, with a model of the scintillator bucket simulated by an analysis tool called RAT, the light yield of the scintillator could be determined by comparing data measurements with simulations. This allowed the light yield, one of the main optical properties of the scintillator, to be measured and that value to be corrected in the Monte Carlo. The bucket was deployed both at the centre of the detector and at the bottom. After subtracting backgrounds from radon introduced in the scintillator during preparation and filling, constraints on the amount of Po-210 were obtained. Estimates on the K-40 content of the Nd-loaded scintillator were obtained by analyzing the radon-subtracted background spectra. By comparing the background spectra with the bucket deployed at the bottom of the acrylic vessel with spectra from the bucket at the centre, it was possible to estimate the K-40 content of the acrylic vessel. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2010-09-22 11:55:44.351

Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2003. / Includes bibliographical references (leaves 151-163). Also available in an electronic version.

Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2003. / Includes bibliographical references. Also available in print form.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xiv, 170 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 159-164).