archives@tulane.edu / This dissertation explores the dielectric Huygens metasurface system. High index dielectric discs in a low index medium act as optical nanoantennas and support electric and magnetic dipole resonant modes. The two resonances are separately tunable, allowing both their absolute and relative spectral locations to be controlled. Spectrally overlapping resonances enable high transmissivity with optical phase controllable by the diameter of the nanoantenna elements, providing a critical building block for the development of gradient phased arrays. Conversely, spectrally separated resonances result in a reflectance peak with tunable shape and depth, a useful feature for sensing applications.
The dissertation is divided into four key chapters. Chapter 2 concerns the development of highly efficient gradient Huygens metasurfaces. Design rules are introduced to mitigate the effects of inter-element coupling, and gradient metasurfaces are computationally demonstrated in the ultraviolet, visible, and infrared spectrums, and experimentally demonstrated for infrared light. Chapter 3 investigates the use of these metasurfaces to sense changes in the refractive index of fluids. A computational analysis is shown, demonstrating broad customizability of sensor performance. Detection of salt and CaCl2 in water is demonstrated experimentally. Chapter 4 explores the potential of Huygens metasurfaces for dynamic tunability. Various methods and materials are discussed. Progress towards tunable metasurfaces utilizing vanadium dioxide (VO2) nanoantennas is highlighted. Chapter 5 describes a unique interferometric measurement tool designed for the characterization of dynamic and ultra-thin materials and metasurfaces. In summary, we explore the unique physics of highly resonant Huygens metasurfaces and pursue their use in a number of promising applications. / 1 / Adam Ollanik
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_90919 |
| Date | January 2019 |
| Contributors | Adam, Ollanik (author), Escarra, Matthew (Thesis advisor), School of Science & Engineering Physics and Engineering Physics (Degree granting institution) |
| Publisher | Tulane University |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | electronic, pages: 152 |
| Rights | 12 months, Copyright is in accordance with U.S. Copyright law. |
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