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McKell, Chad 2016-01-11T09:35:23Z 2018-01-10T09:30:09Z 2015 https://wakespace.lib.wfu.edu/handle/10339/57431 Optical trapping is a useful tool for manipulating microscopic particles and probing the physical interactions of matter. However, previous optical trapping techniques introduced complications for analyzing Brownian particle diffusion in viscous media because they either restricted the particles' motion or trapped the particles too close to a surface. To our knowledge, this thesis presents the first realization of two-dimensional, transverse tracking of Brownian microparticles in multiple, surface-isolated traps. To accomplish this, we used an axicon-generated, zeroth-order Bessel beam standing wave whose parameters were adjusted to allow tight axial confinement and loose transverse confinement of microscopic-sized particles in the central maximum of the Bessel beam. We chose a Bessel beam because its unique non-diffracting and self-healing properties provided distinct advantanges over a Gaussian beam. In particular, a Bessel beam standing wave was shown to produce optical potential wells that are more abundant, uniform, and stable than those of a Gaussian standing wave. en Wake Forest University Bessel beam Brownian diffusion optical trapping optics standing wave Confinement and Tracking of Brownian Particles in a Bessel Beam Standing Wave Thesis Bonin, Keith D Holzwarth, George Williams, Richard T. Physics 2018-01-10 open.access