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Articles 1 - 12 of 12

Full-Text Articles in Physics

Antimatched Electromagnetic Metasurfaces For Broadband Arbitrary Phase Manipulation In Reflection, Odysseas Tsilipakos, Thomas Koschny, Costas M. Soukoulis Jan 2018

Antimatched Electromagnetic Metasurfaces For Broadband Arbitrary Phase Manipulation In Reflection, Odysseas Tsilipakos, Thomas Koschny, Costas M. Soukoulis

Ames Laboratory Accepted Manuscripts

Metasurfaces impart phase discontinuities on impinging electromagnetic waves that are typically limited to 0–2π. Here, we demonstrate that multiresonant metasurfaces can break free from this limitation and supply arbitrarily large, tunable time delays over ultrawide bandwidths. As such, ultrathin metasurfaces can act as the equivalent of thick bulk structures by emulating the multiple geometric resonances of three-dimensional systems that originate from phase accumulation with effective material resonances implemented on the surface itself via suitable subwavelength meta-atoms. We describe a constructive procedure for defining the required sheet admittivities of such metasurfaces. Importantly, the proposed approach provides an exactly linear phase ...


Photonicstd-2d: Modeling Light Scattering In Periodic Multilayer Photonic Structures, Alexey Bondarev, Shaimaa Azzam, Zhaxylyk Kudyshev, Alexander V. Kildishev Aug 2016

Photonicstd-2d: Modeling Light Scattering In Periodic Multilayer Photonic Structures, Alexey Bondarev, Shaimaa Azzam, Zhaxylyk Kudyshev, Alexander V. Kildishev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Efficient modeling of electromagnetic processes in optical and plasmonic metamaterials is important for enabling new and exciting ways to manipulate light for advanced applications. In this work, we put together a tool for numerical simulation of propagation of normally incident light through a nanostructured multilayer composite material. The user builds a unit cell of a given material layer-by-layer starting from a substrate up to a superstrate, splitting each layer further into segments. The segments are defined by width and material -- dielectric, metal or active medium. Simulations are performed with the finite difference time domain (FDTD) method. A database of common ...


Nanophotonics For Dark Materials, Filters, And Optical Magnetism, Mengren Man Aug 2016

Nanophotonics For Dark Materials, Filters, And Optical Magnetism, Mengren Man

Open Access Dissertations

Research on nanophotonic structures for three application areas is described, a near perfect optical absorber based on a graphene/dielectric stack, an ultraviolet bandpass filter formed with an aluminum/dielectric stack, and structures exhibiting homogenizable magnetic properties at infrared frequencies. The graphene stack can be treated as a effective, homogenized medium that can be designed to reflect little light and absorb an astoundingly high amount per unit thickness, making it an ideal dark material and providing a new avenue for photonic devices based on two-dimensional materials. Another material stack arrangement with thin layers of metal and insulator forms a multi-cavity ...


Wave Interaction With Epsilon-Znd-Mu-Near-Zero (Emnz) Platforms And Nonreciprocal Metastructures, Ahmed Mohamed Abdelwahab Mahmoud Jan 2016

Wave Interaction With Epsilon-Znd-Mu-Near-Zero (Emnz) Platforms And Nonreciprocal Metastructures, Ahmed Mohamed Abdelwahab Mahmoud

Publicly Accessible Penn Dissertations

The concept of metamaterials has offered platforms for unconventional tailoring and manipulation of the light-matter interaction. In this dissertation, we explore several concepts and designs within this scope. We investigate some of the electromagnetic characteristics of the concept of “static optics”, i.e., wave interaction with structures in which both the relative effective permittivity and permeability attain near-zero values at a given operating frequency and thus the spatial distributions of the electric and magnetic fields exhibit curl-free features, while the fields are temporally dynamic. Using such structures, one might in principle ‘open up’ and ‘stretch’ the space, and have regions ...


Intensity Control Of Dielectric Barrier Discharge Filaments, Matthew Crawford Paliwoda Jan 2016

Intensity Control Of Dielectric Barrier Discharge Filaments, Matthew Crawford Paliwoda

Masters Theses

"When operated in a filamentary mode, a volume dielectric barrier discharge (DBD) is known to produce patterned plasma structures. These structures are currently being explored for reconfigurable metamaterial applications. In this work the presence and intensity of a single filament, within an array of filaments, was controlled by adjusting the voltage to that filament's individual needle electrode. The current, voltage, and time-averaged normalized light intensity were measured while varying the voltage of the needle through a self-biasing resistance. For a 7.5 kV, 3.2 kHz DBD in air, the needle-controlled filament intensity varies from that of the surrounding ...


Plasmonics On The Slope Of Enlightenment: The Role Of Transition Metal Nitrides, U. Guler, A. Kildishev, A. Boltasseva, V. Shalaev Jan 2015

Plasmonics On The Slope Of Enlightenment: The Role Of Transition Metal Nitrides, U. Guler, A. Kildishev, A. Boltasseva, V. Shalaev

U. Guler

The key problem currently faced by plasmonics is related to material limitations. After almost two decades of extreme excitement and research largely based on the use of noble metals, scientists have come to a consensus on the importance of exploring alternative plasmonic materials to address application-specific challenges to enable the development of new functional devices. Such a change in motivation will undoubtedly lead to significant advancements in plasmonics technology transfer and could have a revolutionary impact on nanophotonic technologies in general. Here, we report on one of the approaches that, together with other new material platforms, mark an insightful technology-driven ...


A Metamaterial Path Towards Optical Integrated Nanocircuits, Fereshteh Abbasi Mahmoudabadi Jan 2015

A Metamaterial Path Towards Optical Integrated Nanocircuits, Fereshteh Abbasi Mahmoudabadi

Publicly Accessible Penn Dissertations

Metamaterials are known to demonstrate exotic electromagnetic and optical properties. The extra control over manipulation of waves and fields afforded by metamaterials can be exploited towards exploring various platforms, e.g., optical integrated circuits. Nanophotonic integrated circuits have been the topic of past and ongoing research in multiple fields including, but not limited to, electrical engineering, optics and materials science. In the present work, we theoretically study and analyze metamaterial properties that can be potentially utilized in the future design of optical integrated circuits. On this path, we seek inspiration from electronics to tackle multiple issues in developing such layered ...


Quantum Levitation Using Metamaterials, Venkatesh K. Pappakrishnan Jul 2014

Quantum Levitation Using Metamaterials, Venkatesh K. Pappakrishnan

Doctoral Dissertations

The emergence of an attractive vacuum force (Casimir force) between two purely dielectric materials can lead to an increase in the friction and the stiction effects in nanoscale devices, resulting in degradation or decreased performance. Thus, it is of high practical importance that the conditions for the reversal of the Casimir force from attractive to repulsive are identified. Although the repulsive Casimir force has been considered for high dielectric materials as an intermediate (between the plates) medium, so far no realistic system has been proposed that can demonstrate quantum levitation with air/vacuum as a host medium. Since air is ...


Digitally Manufactured Spatially Variant Photonic Crystals, Javier Jair Pazos Jan 2014

Digitally Manufactured Spatially Variant Photonic Crystals, Javier Jair Pazos

Open Access Theses & Dissertations

Metamaterials and photonic crystals are engineered composites that exhibit electromagnetic properties superior to those found in nature. They have been shown to produce novel and useful phenomena that allow extraordinary control over the electromagnetic field. One of these phenomena is self-collimation, an effect observed in photonic crystals in which a beam of light propagates without diffraction and is forced to flow in the direction of the crystal. Self-collimation however, like many of the mechanisms enabled through dispersion engineering, is effective in directions only along the principal axes of the lattice. To this effect, a general purpose synThesis procedure was developed ...


Large Area Conformal Infrared Frequency Selective Surfaces, Jeffrey D'Archangel Jan 2014

Large Area Conformal Infrared Frequency Selective Surfaces, Jeffrey D'Archangel

Electronic Theses and Dissertations

Frequency selective surfaces (FSS) were originally developed for electromagnetic filtering applications at microwave frequencies. Electron-beam lithography has enabled the extension of FSS to infrared frequencies; however, these techniques create sample sizes that are seldom appropriate for real world applications due to the size and rigidity of the substrate. A new method of fabricating large area conformal infrared FSS is introduced, which involves releasing miniature FSS arrays from a substrate for implementation in a coating. A selective etching process is proposed and executed to create FSS particles from crossed-dipole and square-loop FSS arrays. When the fill-factor of the particles in the ...


Engineering Optical Properties Using Plasmonic Nanostructures, Venkata Ananth Tamma Apr 2012

Engineering Optical Properties Using Plasmonic Nanostructures, Venkata Ananth Tamma

Electrical, Computer & Energy Engineering Graduate Theses & Dissertations

Plasmonic nanostructures can be engineered to take on unusual optical properties not found in natural materials. The optical responses of plasmonic materials are functions of the structural parameters and symmetry of the nanostructures, material parameters of the nanostructure and its surroundings and the incidence angle, frequency and polarization state of light. The scattering and hence the visibility of an object could be reduced by coating it with a plasmonic material. In this thesis, presented is an optical frequency scattering cancelation device composed of a silicon nanorod coated by a plasmonic gold nanostructure. The principle of operation was theoretically analyzed using ...


Transformation Optics Using Graphene: One-Atom-Thick Optical Devices Based On Graphene, Ashkan Vakil Jan 2012

Transformation Optics Using Graphene: One-Atom-Thick Optical Devices Based On Graphene, Ashkan Vakil

Publicly Accessible Penn Dissertations

Metamaterials and transformation optics have received considerable attention in the recent years, as they have found an immense role in many areas of optical science and engineering by offering schemes to control electromagnetic fields. Another area of science that has

been under the spotlight for the last few years relates to exploration of graphene, which is formed of carbon atoms densely packed into a honey-comb lattice. This material exhibits unconventional electronic and optical properties, intriguing many research groups across

the world including us. But our interest is mostly in studying interaction of electromagnetic waves with graphene and applications that might ...