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Full-Text Articles in Engineering

Gold-Semiconductor Photocatalysts For Water Treatment Under Visible And Ultraviolet Light, Daniel Willis Mar 2021

Gold-Semiconductor Photocatalysts For Water Treatment Under Visible And Ultraviolet Light, Daniel Willis

LSU Doctoral Dissertations

Water scarcity threatens the lives of millions of people worldwide. It is imperative to improve the energy efficiency and affordability of water treatment methods to avoid a looming water-energy crisis. To meet this challenge, I have pursued research on the use of sunlight—our most reliable and abundant source of energy—to drive water treatment through photocatalysis. I explored the literature and found gold-semiconductor materials to hold promise for harvesting sunlight and catalyzing the breakdown of waterborne contaminants. Initially, I designed a novel optical cavity with gold (Au) nanoparticles on a zinc oxide / titania (TiO2) / aluminum film stack …


Point-Of-Care Devices For Therapeutic, Medical And Environmental Applications, Alisha Prasad Sep 2020

Point-Of-Care Devices For Therapeutic, Medical And Environmental Applications, Alisha Prasad

LSU Doctoral Dissertations

Point-of-care testing (POCT) or Point-of-use (POU) devices or technologies are defined as testing aids that are capable for onsite use or testing. The key advantages of POCT are low sample volume, quick onsite diagnosis, high accuracy, and cost-effectiveness. POCT has the potential and the benefits to facilitate better health care management by rapid routine diagnosis and monitoring. To reach this goal, several researchers as well as the healthcare industry over a few years have conducted cutting edge research to bring science to technology by developing smart diagnostic devices capable of performing as per patient profiles and make personalized health care …


Unidirectional And Nonreciprocal Nanophotonic Devices Based On Graphene And Magneto-Optical Materials, Vahid Foroughi Nezhad Oct 2019

Unidirectional And Nonreciprocal Nanophotonic Devices Based On Graphene And Magneto-Optical Materials, Vahid Foroughi Nezhad

LSU Doctoral Dissertations

In this dissertation, we first introduce compact tunable spatial mode converters for graphene parallel plate (GPP) waveguides. The converters are reciprocal and based on spatial modulation of graphene’s conductivity. The wavelength of operation of the mode converters is tunable in the mid-infrared wavelength range by adjusting the chemical potential of a strip on one of the graphene layers of the GPP waveguides. We also introduce optical diodes for GPP waveguides based on a spatial mode converter and a coupler, which consists of a single layer of graphene placed in the middle between the two plates of two GPP waveguides. \par …


Design And Optimization Of Nanoplasmonic Waveguide Devices, Pouya Dastmalchi Jan 2015

Design And Optimization Of Nanoplasmonic Waveguide Devices, Pouya Dastmalchi

LSU Doctoral Dissertations

In this dissertation, we introduce compact absorption switches consisting of plasmonic metal-dielectric-metal (MDM) waveguides coupled to multisection cavities. The optimized multisection cavity switches lead to greatly enhanced modulation depth compared to optimized conventional Fabry-Perot cavity switches. We find that the modulation depth of the optimized multisection cavity switches is greatly enhanced compared to the optimized conventional Fabry-Perot cavity switches due to the great enhancement of the total electromagnetic field energy in the cavity region. We then investigate how to improve the computational efficiency of the design of nanoplasmonic devices. More specifically, we show that the space mapping algorithm, originally developed …


Plasmonic Devices For Manipulating Light At The Nanoscale: Slow-Light Waveguides And Compact Couplers, Yin Huang Jan 2012

Plasmonic Devices For Manipulating Light At The Nanoscale: Slow-Light Waveguides And Compact Couplers, Yin Huang

LSU Doctoral Dissertations

In this dissertation, I explore new plasmonic structures and devices for manipulating light at the nanoscale: slow-light waveguides and compact couplers. I first introduce a plasmonic waveguide system, based on a plasmonic analogue of electromagnetically induced transparency (EIT), which supports a subwavelength slow-light mode, and exhibits a small group velocity dispersion. The system consists of a periodic array of two metal-dielectric-metal (MDM) stub resonators side-coupled to a MDM waveguide. Decreasing the frequency spacing between the two resonances increases the slowdown factor and decreases the bandwidth of the slow-light band. I also show that there is a trade-off between the slowdown …