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Theses/Dissertations

University of Central Florida

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Articles 571 - 575 of 575

Full-Text Articles in Physics

Monolithic Integration Of Dual Optical Elements On High Power Semicond, Laurent Vaissie Jan 2004

Monolithic Integration Of Dual Optical Elements On High Power Semicond, Laurent Vaissie

Electronic Theses and Dissertations

This dissertation investigates the monolithic integration of dual optical elements on high power semiconductor lasers for emission around 980nm wavelength. In the proposed configuration, light is coupled out of the AlGaAs/GaAs waveguide by a low reflectivity grating coupler towards the substrate where a second monolithic optical element is integrated to improve the device performance or functionality. A fabrication process based on electron beam lithography and plasma etching was developed to control the grating coupler duty cycle and shape. The near-field intensity profile outcoupled by the grating is modeled using a combination of finite-difference time domain (FDTD) analysis of the nonuniform …


Towards Direct Writing Of 3-D Photonic Circuits Using Ultrafast Lasers, Arnaud Zoubir Jan 2004

Towards Direct Writing Of 3-D Photonic Circuits Using Ultrafast Lasers, Arnaud Zoubir

Electronic Theses and Dissertations

The advent of ultrafast lasers has enabled micromachining schemes that cannot be achieved by other current techniques. Laser direct writing has emerged as one of the possible routes for fabrication of optical waveguides in transparent materials. In this thesis, the advantages and limitations of this technique are explored. Two extended-cavity ultrafast lasers were built and characterized as the laser sources for this study, with improved performance over existing systems. Waveguides are fabricated in oxide glass, chalcogenide glass, and polymers, these being the three major classes of materials for the telecommunication industry. Standard waveguide metrology is performed on the fabricated waveguides, …


Scintillation Behind The Collecting Lens Of A Receiver, Clarissa A. Fleming Russell Jan 2001

Scintillation Behind The Collecting Lens Of A Receiver, Clarissa A. Fleming Russell

Retrospective Theses and Dissertations

One of the negative effects that a laser beam experiences as it propagates through the atmosphere is intensity fluctuations or scintillation. Because scintillation-- as it pertains to laser radar and laser satellite communication systems-- is the main subject of this research, the assumption of an optical element ( such as a Gaussian lens) along the propagation path in front of the detector is valid. The mathematical addition of optical elements to the propagation path is treated using the ABCD ray matrix method. The expression for scintillation is derived, analyzed, and numerically calculated for positions to the left and right of …


Optical Performance Of Grazing Incidence X-Ray / Euv Telescopes For Space Science Applications, Patrick Louis Thompson Jan 2000

Optical Performance Of Grazing Incidence X-Ray / Euv Telescopes For Space Science Applications, Patrick Louis Thompson

Retrospective Theses and Dissertations

The science and technology of X-rays has only been part of human achievement for the past 100 years, while the study of image formation in general has endured for as long as 1000 years. The ability to conceive, design, and fabricate X-ray imagers, moreover, has existed for only the past 70 years, and X-ray astronomical telescopes have been in use for a mere 35 years. Considering that aplanatic, normal incidence telescope designs required more than 400 years to perfect, it is most interesting to note that the development of ‘aplanatic’ grazing incidence telescopes has taken only about 40 years. In …


Evaluation Of The Reduction Of The Nonadiabatic Hyperspherical Radial Equation To The First Order, Steven L. Carbon Jan 1987

Evaluation Of The Reduction Of The Nonadiabatic Hyperspherical Radial Equation To The First Order, Steven L. Carbon

Retrospective Theses and Dissertations

In this paper we examine the effectiveness of reducing the second order radial equation, of the hyperspherical coordinate solution to the two-electron Schrodinger equation, into a set of coupled first order linear equations as suggested by Klar. All results have been obtained in a completely nonadiabatic formalism thereby ensuring accuracy. We arrive at the conclusion that our application of the reduction process is in some way inconsistent and suggest a possible resolution to this anomaly.