A5035648104- Metamaterials and Metasurfaces Applications
- Advanced Antenna and Metasurface Technologies
- Plasmonic and Surface Plasmon Research
- Antenna Design and Analysis
- Photonic Crystals and Applications
- Photonic and Optical Devices
- Antenna Design and Optimization
- Gold and Silver Nanoparticles Synthesis and Applications
- Orbital Angular Momentum in Optics
- Random lasers and scattering media
- Optical Wireless Communication Technologies
- Ocean Waves and Remote Sensing
- Underwater Acoustics Research
- Microwave Engineering and Waveguides
- Electromagnetic Scattering and Analysis
- Quantum Mechanics and Non-Hermitian Physics
- Urban Heat Island Mitigation
- Microwave and Dielectric Measurement Techniques
- Thermal Radiation and Cooling Technologies
- Strong Light-Matter Interactions
- Near-Field Optical Microscopy
- Neural Networks and Reservoir Computing
- Optical Coatings and Gratings
- Optical Network Technologies
- Superconducting and THz Device Technology
The Ohio State University
2024
National Technical University of Athens
2024
Chapman University
2021-2024
University of Pennsylvania
2017-2020
The University of Texas at Austin
2012-2018
University of Tehran
2010
By applying the optical nanocircuit concepts to metasurfaces, we propose an effective route locally control light transmission over a deeply subwavelength scale. This concept realizes equivalent of transmit-array, whose use is demonstrated for bending and focusing with unprecedented efficiency distance, crucial benefits nano-optics applications. These findings may lead large improvements in manipulation processing nanoscale signals conformal Si-compatible substrates.
Solving equations with waves Signal processing of light can be used to represent certain mathematical functions and perform computational tasks on signals or images in an analog fashion. Such typically requires complex systems bulk optical elements such as lenses, filters, mirrors. Mohammadi Estakhri et al. demonstrate that specially designed nanophotonic structures take input waveforms encoded functions, manipulate them, provide output is the integral functions. The results, demonstrated...
Metasurfaces are engineered systems that enable advanced control of electromagnetic waves over deeply subwavelength thicknesses. Researchers make a careful study the use metasurfaces to transform impinging optical wave front.
Recent advances in metasurfaces, i.e., artificial arrays of engineered inclusions assembled over a thin surface, have opened promising venues to control electromagnetic waves unique and unprecedented ways, by means locally engineering their near-field wave–matter interactions. Gradient or nonperiodic metasurfaces are one the most exciting recent nano-optics, due promise enabling ultimate light molding, both far-field, with large efficiency minimal footprint. These surfaces characterized...
The negative refraction and evanescent-wave canalization effects supported by a layered metamaterial structure obtained alternating dielectric plasmonic layers is theoretically analyzed. By using transmission-line analysis, we formulate way to rapidly analyze the operation for given available materials over broad range of frequencies design parameters, apply it broaden bandwidth refraction. Our analytical model also applied explore possibility employing active loss compensation. Nonlinear...
Using atomically smooth epitaxial silver films, new optical permittivity highlighting significant loss reduction in the visible frequency range is extracted. Largely enhanced propagation distances of surface plasmon polaritons are measured, confirming low intrinsic silver. The free extrinsic spectral features associated with grain boundaries and localized plasmons inevitably present thermally deposited films.
In this work we present the concept and design of an ultrathin (\ensuremath{\lambda}/22) terahertz (THz) unidirectional carpet cloak based on local phase compensation approach enabled by gradient metasurfaces. A triangular surface bump with center height 4.1 mm (1.1\ensuremath{\lambda}) tilt angle 20\ifmmode^\circ\else\textdegree\fi{} is covered a metasurface composed array suitably designed closed ring resonators transverse impedance. The provide wide range control for reflection small...
Using a suitably designed, ultra-thin graded metasurface, we demonstrate the possibility of hiding an arbitrarily shaped/sized object from impinging plane wave. The metasurface is tailored to provide abrupt, inhomogeneous discontinuity electromagnetic field that compensates for unwanted scattering created by object. desired distribution generated based on equivalence principle through reconstruction electric/magnetic fields at location, resembling flat conducting surface external observer....
A metasurface carpet cloak for millimeter-wave range with polarization-independent performance is experimentally demonstrated. It shown that the able to mimic ground plane by fully restoring amplitude and phase distributions both transverse electric magnetic polarizations, a relatively wide frequency angular widths response. As service our authors readers, this journal provides supporting information supplied authors. Such materials are peer reviewed may be re-organized online delivery, but...
Metasurfaces, or phase-engineered quasi-2D interfaces, enable a large degree of control over the reflection, refraction, and transmission light. Here we demonstrate design realization visible light gradient metasurface tailored for highly efficient back reflection based on Huygens–Fresnel principle. The emulates functionality Littrow grating, capable efficiently channeling into first negative Floquet order broad angular range bandwidth at frequencies. Our theoretical results predict unitary...
We propose a comprehensive scheme for the efficient design of graded optical metasurfaces capable rerouting impinging energy at will in flexible way. show that carefully designed conjoined nanoelements may be used as basic building blocks to arbitrarily shape reflected phase front, while providing large controllability and low loss over deeply subwavelength thicknesses. The metasurface elements are using transmission line concepts combined with nanocircuit theory, they can realized...
Abstract By using silver nanoplatelets with a widely tunable localized surface plasmon resonance (LSPR) and their corresponding local field enhancement, here we show large manipulation of plasmonic enhanced upconversion in NaYF4:Yb 3+ /Er nanocrystals at the single particle level. In particular, that when nanolplatelets is tuned to 656 nm, matching emission wavelength, an enhancement factor ~5 obtained. However, 980 nanocrystal absorption achieve ~22 folds. The precise geometric arrangement...
A necessary, but not sufficient, condition for parity-time ($P\phantom{\rule{0}{0ex}}T$) symmetry to hold in an optical system is that spatially separated gain and loss must be exactly balanced. This study introduces generalized $P\phantom{\rule{0}{0ex}}T$-symmetric structures can have asymmetric unbalanced gain-loss profiles, yet offer similar scattering properties phase transitions as traditional ones. The concept of general $P\phantom{\rule{0}{0ex}}T$ may help reduce the threshold...
Absorption and scattering are inherently related, as it is not possible to absorb power without creating a far-field shadow. We show, however, that properly overlapped resonant modes in suitably designed system may principle lead arbitrarily large absorption levels, while at the same time minimizing total scattering. discuss fundamental limits on of an arbitrary receiving envision composite nanoparticle demonstrates concept minimum-scattering superabsorber, with potential applications energy...
Atomically thin lateral heterostructures based on transition metal dichalcogenides have recently been demonstrated. In monolayer dichalcogenides, exciton energy transfer is typically limited to a short range (~1 μm), and additional losses may be incurred at the interfacial regions of heterostructure. To overcome these challenges, here we experimentally implement planar metal-oxide-semiconductor structure by placing WS2/MoS2 heterostructure top an Al2O3-capped Ag single-crystalline plate. We...
In this work, we experimentally demonstrate metasurface-enhanced photoresponse in organic photodetectors. We have designed and integrated a metasurface with broadband functionality into an photodetector, the goal of significantly increasing absorption light generated photocurrent from 560 up to 690 nm. discuss how can be fabrication photodiode. Our results show large gains responsivity 1.5× 2× between
Optical metasurfaces, typically referred to as two-dimensional metamaterials, are arrays of engineered subwavelength inclusions suitably designed tailor the light properties, including amplitude, phase and polarization state, over deeply scales. By exploiting anomalous localized interactions surface elements with optical waves, metasurfaces can go beyond functionalities offered by conventional diffractive gratings. The innate simplicity implementation distinct underlying physics their...
Abstract Machine learning provides a promising platform for both forward modeling and the inverse design of photonic structures. Relying on data-driven approach, machine is especially appealing situations when it not feasible to derive an analytical solution complex problem. There has been great amount recent interest in constructing models suitable different electromagnetic problems. In this work, we adapt region-specified approach multilayered nanoparticles. Given high computational cost...
Confining and controlling electromagnetic energy typically involves a highly resonant phenomenon, especially when subwavelength confinement is desired. Here, we present class of nonresonant, self-dual planar metastructures capable protected transmission from one side to the other, through arbitrarily narrow apertures. It shown that in form matched propagating modes independent thickness specific composition surface. We analytically prove condition sufficient guarantee 100% robust presence...
Anomalous resonances in properly shaped plasmonic nanostructures can principle lead to infinite absorption/gain efficiencies over broad bandwidths of operation. By developing a closed-form analytical solution for the fields scattered by conjoined hemicylinders, we outline fundamental physics behind these phenomena, associated with broadband adiabatic focusing surface plasmons at nanoscale. Over continuous frequency range, our proposed composite nanostructure shows finite amount...
We present here tunable and reconfigurable designs of linear nonlinear plasmonic hyperbolic metamaterials. Rich scattering features multilayered composite nanoparticles are demonstrated, which include complex exotic signatures combining multiple dipolar Fano resonances electromagnetic induced transparency (EIT) features. These dipole-dipole multi-Fano responses can be further tuned through altering the properties concentric layers or permittivity core, for instance, by presence...
In this work, we investigate a class of planar photonic structures operating as passive thermoregulators. The radiative cooling process is adjusted through the incorporation phase change material (Vanadium Dioxide, VO 2 ) in conjunction with layer transparent conductive oxide (Aluminum-doped Zinc Oxide, AZO). known to undergo transition from “dielectric” “plasmonic” or “metallic” at critical temperature close 68°C. addition, AZO shows plasmonic properties long-wave infrared spectrum, which,...
We theoretically demonstrate the mechanisms to funnel electromagnetic energy through any desired prescribed aperture field distributions, using transparent metasurfaces with inhomogeneous impedance profiles. It is shown that a single surface sufficient mold near-field distribution at will, while 100% transmission achieved. The results are derived analytically and demonstrated numerical examples of subwavelength localization. A related technique based on Weston condition also discussed. Our...
Adv. Mater. 2014, 26, 6106–6110 The authors have realized that the calculation shown in inset of Figure 2c plotted electric field decay, while they had used intensity decay to define propagation distance for experimental data rest manuscript. plot is corrected here reflect decay. In 2c, graph replotted with semilog predictions. A predicted distances using JC also added. at 632 nm from all three predictions are now labelled. Some values quoted text were based on this incorrect as a result...