Browsing by Author "Gerislioglu, Burak"

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    Bound States in the Continuum for Metaphotonics
    (2021-08-09) Gerislioglu, Burak; Nordlander, Peter
    Identified almost a century ago by early quantum physicists, the study of bound states has become an active field of research that continues to surprise year after year with groundbreaking innovation opportunities and its connections to other research areas. Based on the physics of artificially engineered resonant metallic or all-dielectric building blocks (e.g., 3D and flatland metastructures), which can confine light at subwavelength scales and create high-density concentrations of electromagnetic energy, researchers are driving advances in nanophotonics and bringing us much closer to all-optical communication and data processing. In light of these, this thesis reports: (i) scalable plasmonic Fano-resonant metasurfaces for the generation of visible color and (ii) photonic quasi-infinite metastructures for refractometric sensing and sustainable chemistry. Chapter 1 discusses the limits and challenges associated with the fabrication of large-scale plasmonic metasurfaces because of fabrication imperfections, especially when using aluminum (Al). Chapter 2 demonstrates an all-dielectric metasurface design, made of periodic arrays of scatterers, towards next-generation thermo/photo-catalysis and refractometric sensing by exploiting the sharp resonances induced by bound states in the continuum (BICs), an intriguing concept in light-matter interactions.
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    Nanophotonics for Novel Refractive Index Sensing and Deep UV Light Generation
    (2020-07-22) Gerislioglu, Burak; Nordlander, Peter J.
    From its very birth, the study of nanophotonics has become a vibrant field of research that continues to surprise year after year with disruptive innovation opportunities. Using artificially engineered subwavelength metallic or all-dielectric building blocks (e.g., 3D and flatland metastructures), researchers now control the flow of light far beyond the classical diffraction limits and unveil unique functionalities not accessible in nature. In light of these, this thesis reports: (i) refractive index sensing characteristics of a plasmonic metal dimer on a substrate of the same metal and (ii) third harmonic generation (THG) of deep ultraviolet (DUV) light using toroidal dipole-based plasmonic meta-atoms. Chapter 1 presents the developed monolithic metal dimer-on-film structure in-detail, where the implementation of such all-metal magnetic dipole-resonant metasurface provides high-performance localized surface plasmon resonance (LSPR)- and surface lattice resonance (SLR)-based plasmonic sensors. Chapter 2 demonstrates a reliable candidate to generate high-energy light using toroidal excitations (an intriguing concept in light-matter interactions), as the first example of its kind.
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    Toroidal Dipole-Enhanced Third Harmonic Generation of Deep Ultraviolet Light Using Plasmonic Meta-atoms
    (American Chemical Society, 2019) Ahmadivand, Arash; Semmlinger, Michael; Dong, Liangliang; Gerislioglu, Burak; Nordlander, Peter; Halas, Naomi J.; Laboratory for Nanophotonics
    The harmonic generation of light with plasmonic and all-dielectric nanostructures has gained much recent interest. This approach is especially promising for short wavelength (i.e., ultraviolet (UV)) generation, where conventional nonlinear crystals reach their limits both in transparency and in their ability to achieve phase-matching between the input and output fields. Here, we demonstrate that the third harmonic generation of deep UV light in an indium tin oxide (ITO) film can be substantially enhanced by a metasurface consisting of metallic toroidal meta-atoms covered with an alumina layer for protection against laser-induced damage. This approach combines the benefits of the large nonlinear susceptibility of ITO with the unique field enhancement properties of a toroidal metasurface. This ITO–meta-atom combination produces a third harmonic signal at a wavelength of 262 nm that is nominally five times larger than that of an ITO film patterned with a conventional hotspot-enhanced plasmonic dimer array. This result demonstrates the potential for toroidal meta-atoms as the active engineered element in a new generation of enhanced nonlinear optical materials and devices.