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dc.contributor.advisorDholakia, Kishan
dc.contributor.advisorMazilu, Michael
dc.contributor.authorMourka, Areti
dc.description.abstractIn this thesis, an investigation into the modal characteristics of novel beam shapes is presented. Sculpting the phase profile of a Gaussian beam can result in the generation of a beam with unique properties. Described in this thesis are Laguerre-Gaussian (LG), Hermite-Gaussian (HG) and Bessel beams (BBs). The diffraction of LG beam modes from a triangular aperture is explored and this effect can be used for the efficient measurement of the azimuthal mode index l that indicates the number of multiples of 2π of phase changes that the field displays around one circumference of the optical axis. In this study, only LG beams with zero radial mode index p, with p + 1 denoting the number of bright high intensity concentric rings around the optical axis, were considered. Then, a powerful approach to simultaneously determine both mode indices of a pure LG beam using the principal component analysis (PCA) algorithm on the observed far-field diffraction patterns was demonstrated. Owing to PCA algorithm, the shape of the diffracting element used to measure the mode indices is in fact of little importance and the crucial step is ‘training’ any diffracting optical system and transforming the observed far-field diffraction patterns into the uncorrelated variables (principal components). Our PCA method is generic and it was extended to other families of light fields such as HG, Bessel and superposed beams. This reinforces the widespread applicability of this method for various applications. Finally, both theoretically and experimentally investigations using interferometry show the definitive linkage between both the radial and azimuthal mode indices of a partially coherent LG beam and the dislocation rings in the far-field cross-correlation function (CCF).en_US
dc.publisherUniversity of St Andrews
dc.rightsCreative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported
dc.subjectLaser beam shapingen_US
dc.subjectDiffraction and gratingsen_US
dc.subjectLasers and laser opticsen_US
dc.subjectOrbital angular momentum (OAM)en_US
dc.subjectSingular optics - optical vorticesen_US
dc.subjectAdaptive opticsen_US
dc.subjectApplied physicsen_US
dc.subject.lcshBeam opticsen_US
dc.subject.lcshLaser beamsen_US
dc.subject.lcshAngular momentumen_US
dc.titleProbing the modal characteristics of novel beam shapesen_US
dc.type.qualificationnamePhD Doctor of Philosophyen_US
dc.publisher.institutionThe University of St Andrewsen_US
dc.publisher.departmentSchool of Physics & Astronomyen_US

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Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported
Except where otherwise noted within the work, this item's licence for re-use is described as Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported