Near-field Optical Characterization of Mesoscale Structures

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The work described in this dissertation focuses on the optical characterization of micron-sized structures with mesoscale (100-1000 nm) features to investigate of the optical analog to the quantum corral. Lithographically patterned arrays of metallic rings and ellipses were used to study how light can be manipulated and confined within these corral structures. Near-field optical results demonstrated that it was possible to confine electromagnetic (EM) waves within the circular corrals were produced, and standing wave patterns similar to those observed in the quantum corrals. We showed that only certain wavelengths of light could be efficiently sustained inside of these structures to produce a bright spot at the center of the corral. Elliptical corrals, with different eccentricities, were further investigated for their ability to tailor the standing waves by varying the polarization of the incident light. The results revealed that ellipses with larger eccentricities had the ability to modulate light at the focal points to produce bright or dark spots depending on the wavelength of the incident light. Lithographic techniques were also used to generate circular structures of CdSe/ZnS quantum dots (QDs). The photoluminescence (PL) properties of these rings of close-packed QDs were measured, and a red-shift, which was attributed to either the change of the dielectric environment around the QDs or to the resonant energy transfer between the QDs, in the emission peak was observed. The final chapter of this thesis describes a set of experiments that were developed to supplement lecture-only courses on nanotechnology in undergraduate curriculum. The labs were based on soft lithographic techniques, including replica molding, micro-molding in capillaries, and micro-contact printing and etching. These simple experiments require only readily available and inexpensive materials such as compact discs, glass microscope slides, poly(dimethylsiloxane), and polyurethane.

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  • 08/28/2018
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