A5080528426- Plasmonic and Surface Plasmon Research
- Thermal Radiation and Cooling Technologies
- Silicon Carbide Semiconductor Technologies
- Semiconductor materials and devices
- Photonic and Optical Devices
- GaN-based semiconductor devices and materials
- Silicon Nanostructures and Photoluminescence
- Photonic Crystals and Applications
- Strong Light-Matter Interactions
- Metamaterials and Metasurfaces Applications
- Graphene research and applications
- Mechanical and Optical Resonators
- Gold and Silver Nanoparticles Synthesis and Applications
- Silicon and Solar Cell Technologies
- Thin-Film Transistor Technologies
- Ga2O3 and related materials
- Semiconductor Quantum Structures and Devices
- Near-Field Optical Microscopy
- Integrated Circuits and Semiconductor Failure Analysis
- Optical properties and cooling technologies in crystalline materials
- Copper Interconnects and Reliability
- Semiconductor materials and interfaces
- Quantum and electron transport phenomena
- Electromagnetic Compatibility and Noise Suppression
- Nanowire Synthesis and Applications
Vanderbilt University
2017-2025
Naval Surface Warfare Center
2024
Center for Nanoscale Science and Technology
2018-2023
Vanderbilt Health
2023
University of Delaware
2021
DuPont (United States)
2021
ORCID
2021
United States Naval Research Laboratory
2010-2019
University of Georgia
2019
The University of Texas at Austin
2019
Abstract The excitation of surface-phonon-polariton (SPhP) modes in polar dielectric crystals and the associated new developments field SPhPs are reviewed. emphasis this work is on providing an understanding general phenomenon, including origin Reststrahlen band, role that optical phonons lattices play supporting sub-diffraction-limited how relatively long phonon lifetimes can lead to low losses observed within these materials. Based overview, achievements attained date potential...
Optical imaging beyond the diffraction limit was one of primary motivations for negative-index metamaterials, resulting in Pendry's perfect lens and more attainable superlens. While these approaches offer sub-diffractional resolution, they do not provide a mechanism magnification image. Hyperbolic (or indefinite-permittivity) metamaterials have been theoretically considered experimentally demonstrated to simultaneously subdiffractive magnification; however, are plagued with low efficiency...
Plasmonics provides great promise for nanophotonic applications. However, the high optical losses inherent in metal-based plasmonic systems have limited progress. Thus, it is critical to identify alternative low-loss materials. One polar dielectrics that support surface phonon polariton (SPhP) modes, where confinement of infrared light aided by phonons. Using fabricated 6H-silicon carbide nanopillar antenna arrays, we report on observation subdiffraction, localized SPhP resonances. They...
Radiation patterns and the resonance wavelength of a plasmonic antenna are significantly influenced by its local environment, particularly substrate. Here, we experimentally explore role dispersive substrates, such as aluminum- or gallium-doped zinc oxide in near infrared 4H-silicon carbide mid-infrared, upon Au antennas, extending from dielectric to metal-like regimes, crossing through epsilon-near-zero (ENZ) conditions. We demonstrate that vanishing index refraction within this transition...
Metasurfaces control light propagation at the nanoscale for applications in both free-space and surface-confined geometries. However, dynamically changing properties of metasurfaces can be a major challenge. Here we demonstrate reconfigurable hyperbolic metasurface comprised heterostructure isotopically enriched hexagonal boron nitride (hBN) direct contact with phase-change material (PCM) single-crystal vanadium dioxide (VO2). Metallic dielectric domains VO2 provide spatially localized...
Abstract The lattice symmetry of a crystal is one the most important factors in determining its physical properties. Particularly, low-symmetry crystals offer powerful opportunities to control light propagation, polarization and phase 1–4 . Materials featuring extreme optical anisotropy can support hyperbolic response, enabling coupled light–matter interactions, also known as polaritons, with highly directional propagation compression deeply sub-wavelength scales 5 Here we show that...
Abstract Anisotropic planar polaritons - hybrid electromagnetic modes mediated by phonons, plasmons, or excitons in biaxial two-dimensional (2D) van der Waals crystals have attracted significant attention due to their fundamental physics and potential nanophotonic applications. In this Perspective, we review the properties of hyperbolic variety methods that can be used experimentally tune them. We argue such natural, media should fairly common uniaxial 2D 1D crystals, identify untapped...
Efforts to create reproducible surface-enhanced Raman scattering (SERS)-based chemical and biological sensors has been hindered by difficulties in fabricating large-area SERS-active substrates with a uniform, SERS response that still provides sufficient enhancement for easy detection. Here we report on periodic arrays of Au-capped, vertically aligned silicon nanopillars are embedded Au plane upon Si substrate. We illustrate these ideal use as sensor templates, they provide large, uniform...
To make graphene technologically viable, the transfer of films to substrates appropriate for specific applications is required. We demonstrate dry epitaxial (EG) from C-face 4H-SiC onto SiO2, GaN and Al2O3 using a thermal release tape. Subsequent Hall effect measurements illustrated that minimal degradation in carrier mobility was induced following process lithographically patterned devices. Correspondingly, large drop concentration observed process, supporting notion gradient density...
This work demonstrates the production of a well-controlled, chemical gradient on surface graphene. By inducing oxygen functional groups, drops water and dimethyl-methylphosphonate (a nerve agent simulant) are "pulled" in direction increasing content, while fluorine gradients "push" droplet motion decreasing content. The is broadly attributed to increasing/decreasing hydrophilicity, which correlated high/low adhesion binding energy. Such tunability chemistry provides additional capabilities...
Low-loss surface phonon polariton (SPhP) modes supported within polar dielectric crystals are a promising alternative to conventional, metal-based plasmonic systems for the realization of nanophotonic components. Here we show that monopolar excitations in 4H-silicon carbide nanopillar arrays exhibit an unprecedented stable efficiency even when resonator filling fraction is varied by order magnitude. This provides powerful mid-IR platform with excellent spectral tunability and strong field...
As an emerging optical material, graphene’s ultrafast dynamics are often probed using pulsed lasers yet the region in which damage takes place is largely uncharted. Here, femtosecond laser pulses induced localized single-layer graphene on sapphire. Raman spatial mapping, SEM, and AFM microscopy quantified damage. The resulting size of damaged area has a linear correlation with fluence. These results demonstrate local modification sp2-carbon bonding structures pulse fluences as low 14 mJ/cm2,...
Abstract The biaxial van der Waals semiconductor α‐phase molybdenum trioxide (α‐MoO 3 ) has recently received significant attention due to its ability support highly anisotropic phonon polaritons (PhPs)—infrared (IR) light coupled lattice vibrations—offering an unprecedented platform for controlling the flow of energy at nanoscale. However, fully exploit extraordinary IR response this material, accurate dielectric function is required. Here, α‐MoO reported by modeling far‐field polarized...
A conventional thermal emitter exhibits a broad emission spectrum with peak wavelength depending upon the operation temperature. Recently, narrowband was realized periodic gratings or single microstructures of polar crystals supporting distinct optical modes. Here, we exploit coupling adjacent phonon-polaritonic nanostructures, demonstrating experimentally that nanometer-scale gaps can control frequency while retaining line widths as narrow 10 cm–1. This achieved by using deeply...
Mie-resonances in vertical, small aspect-ratio and subwavelength silicon nanopillars are investigated using visible bright-field µ-reflection measurements Raman scattering. Pillar-to-pillar interactions were examined by comparing randomly to periodically arranged arrays with systematic variations nanopillar diameter array pitch. First- second-order Mie resonances observed reflectance spectra as pronounced dips minimum reflectances of several percent, suggesting an alternative approach...
We use scanning near-field optical microscopy to study the response of hexagonal boron nitride nanocones at infrared frequencies, where this material behaves as a hyperbolic medium. The obtained images are dominated by series hot rings that occur on sloped sidewalls nanocones. ring positions depend incident laser frequency and nanocone shape. Both dependences consistent with directional propagation phonon polariton rays launched edges zigzag through interior nanocones, sustaining multiple...