Generation of an Elliptical Zeroth-Order Bessel Beam with a Deformable Annular Slit

Date of Award

12-2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Physics

Department

Physics

First Advisor

Raphael A. Guerrero, PhD

Abstract

This dissertation investigates the generation of elliptical Bessel beams though the use of deformable annular slits. The manuscript is divided into three parts: the first discusses slit fabrications, followed by the computational investigations, and finally, the experimental methods. Fabrications using soft-lithography and photolithography yields a deformable slit with an outer diameter of d = 900 ± 7 μm and a slit width of 180 ± 20 μm. Models based on Maxwell's electromagnetic theory predict the elongation of the generated beams along a direction perpendicular to the annular slit strain. The elliptical beam core is also predicted to be invariant in terms of propagation along the z-axis. Experimental elliptical Bessel beams are produced from the annular slit under applied strain. A slit elongated with strain s = 0.13 produces beams with central core eccentricity e = 0.62, effectively demonstrating the generation of elliptical Bessel beams. The horizontal core diameter of the elliptical Bessel beams is found to exhibit non-diffraction from z = 20 cm to z = 30 cm. The horizontal width on average is 260 μm. Generated beams are observed to possess a self-healing property and are semiresilient to diffraction in the far field up to z = 50 cm. The theoretical model effectively predicts the orientation of elliptical Bessel beam profiles in slits with s = 0.13 for propagation distances z = 30 cm to z = 50 cm. The results obtained in this study could potentially contribute to advancements in atom optics, matter-wave microscopy, ultrafast volume structuring and quantum communications.

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