Browsing by Subject "Nanofabrication"

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    Alternative Methods and Materials for use in Plasmonics
    (2019-03) Klemme, Daniel
    Plasmonic devices are extremely useful across a wide variety of fields and have been used for ultra-high-resoulution imaging, drug detection, metamaterials, and single-molecule studies among other things. One major hurdle to achieving useful plasmonic structures is that deeply subwavelength patterns need to be generated, both for coupling the light to the device and to fabricate the device itself. Many plasmonic devices such as optical antennas used for nanofocusing are nonplanar, which vastly increases the difficulty of fabricating subwavelength structures on them. Standard lithographic processes such as photolithography and electron beam lithography are of limited use on three-dimensional substrates, which necessitates the development of novel fabrication techniques. Shadow mask lithography and conformal coating of metallic sidewalls via atomic layer deposition are two techniques that will be used to achieve subwavelength patterning of three-dimensional structures. Additionally, plasmonic materials have typically been dominated by gold and to a lesser extent silver because they exhibit good dielectric properties at optical frequencies and are reasonably robust to ambient conditions. However, these materials do come with their own fabrication limitations that other plasmonically active materials such as titanium nitride and copper do not necessarily have. In particular, atomic layer deposition recipes now exist for titanium nitride that allow sub-10 nm, continuous, and conformal metallic films to be created which opens up the door to novel ultrathin plasmonic structures. In this dissertation, plasmonic structures that were generated using nonstandard nanofabrication techniques and/or metallic materials will be explored, demonstrating the advantages that come with using such techniques and materials.
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    Metallic Nanostructures and Plasmonic Devices for Surface Plasmon Resonance Biosensing
    (2011-08) Im, Hyungsoon
    High-throughput real-time sensing of molecular binding kinetics is important for drug discovery, basic biology, and the emerging field of proteomics. In particular, label-free surface plasmon resonance (SPR) sensing, which harnesses electromagnetic surface waves excited on metallic nanostructures, has been widely used in pharmaceutical development. Despite successful commercialization, the reflection-based configuration of traditional SPR instruments suffer from high cost, low sensing throughput, and incompatibility of studying molecules in cell membranes. In this dissertation, a new SPR biosensor based on plasmonic nanohole arrays made in metallic films is demonstrated. These biosensors are used for multiplexed sensing of molecular interactions in a quantitative manner. The nanohole-based SPR devices measure transmission of normally-incident light and the co-linear optical transmission setup offers simple optical setup and high-resolution imaging capability, leading to high-throughput multiplex kinetic assays for protein microarray applications. Additionally, the nanoholes can readily incorporate lipid membranes to study antibody binding to lipids and membrane-bound proteins. Newly developed nanofabrication methods enable production of large-area nanohole- and nanogap arrays in an inexpensive and high-throughput fashion. These methods may facilitate wide dissemination of nanohole SPR sensing as well as chemical sensing via surface-enhanced Raman spectroscopy