Optical vortices: Angular momentum of light, energy propagation, and imaging.
Item
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Title
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Optical vortices: Angular momentum of light, energy propagation, and imaging.
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Identifier
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AAI3325437
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identifier
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3325437
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Creator
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Sztul, Henry.
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Contributor
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Adviser: Robert R. Alfano
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Date
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2008
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Optics
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Abstract
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The aim of this thesis is to study salient properties of optical vortices. Optical vortices are a class of solution to Maxwell's equations, some having helical wavefronts and bear orbital angular momentum. Methods of generation of ultrashort and polychromatic optical vortices for use in imaging and spectroscopy are discussed. A new imaging technique that utilizes the optical force associated with a vortex is shown to improve image contrast in a turbid medium. Two new classes of beams are shown to have vortices and carry some well defined angular momentum.;In this thesis, I begin by laying down the mathematical origins of optical vortices and the angular momentum of light. Spin and orbital angular momentum are discussed and shown to be associated with Laguerre-Gaussian (LG) beams. Interesting properties of these beams are explored including an experimental and theoretical demonstration of Young's double-slit experiment. The azimuthal phase variation of the LG beam is taken into account when analyzing the interference due to the two slits.;A method of angular dispersion compensation is used to generate femtosecond LG beams. This thesis reports on the first autocorrelation measurements of LG beams. This compensation method is also used to generate supercontinuum vortices. The white light vortices have tremendous potential in applications to optical spectroscopy with orbital angular momentum states.;A new technique is used to image through turbid media that relies on the optical forces associated with a high intensity optical vortex "guide" beam to drag scattering particles out of the path of a low intensity "signal" beam. First the transverse forces due to a Gaussian beam are shown to degrade imaging by pulling scatterers into the path of a second "signal" beam.;Finally, two new classes of optical waves are explored. A new cylindrical vector mode is described and classified as a hybrid-azimuthal polarization imaginary (HAPi) mode that has an azimuthally varying polarization including linear and circular polarization that gives rise to an azimuthally varying angular momentum. The propagation dynamics of optical Airy beams are also numerically analyzed and discussed. This class of beam is shown to have varying linear and angular momentum.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
