J.A. Bossard

William Penn University, Worcester, Massachusetts, United States

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Publications (66)109.46 Total impact

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    Jeremy A. Bossard · Lan Lin · Douglas H. Werner

    Preview · Article · Jan 2016 · Journal of The Royal Society Interface
  • J.A. Bossard · L. Lin · D.H. Werner
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    ABSTRACT: A novel nature-inspired technique is introduced and employed to synthesize fractal random superlattices with custom mirror and multispectral filter properties in the visible spectrum. Fractal random Cantor bars are utilized as a representative model of superlattice structures found in nature. An important benefit of the design methodology is a reduction in the number of parameters required for optimization by a genetic algorithm (GA).
    No preview · Article · May 2015
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    ABSTRACT: While many studies have been conducted on metamaterials at microwave frequencies, comparatively few have examined their use in high-power applications. Here, we perform a general study of metamaterial geometries to identify configurations that are well-suited for utilization in high-power environments. We further develop a genetic algorithm optimization scheme for synthesizing pixelized geometries with artificial magnetic conducting (AMC) properties and reduced maximum field enhancement factor (MFEF).
    No preview · Conference Paper · Jul 2014
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    ABSTRACT: Metamaterials are being applied to the development and construction of many new devices throughout the electromagnetic spectrum. Limitations posed by the metamaterial operational bandwidth and losses can be effectively mitigated through the incorporation of tunable elements into the metamaterial devices. There are wide range of approaches that have been advanced in the literature for adding reconfiguration to metamaterial devices all the way from the RF through the optical regimes, but some techniques are useful only for certain wavelength bands. A range of tuning techniques span from active circuit elements introduced into the resonant conductive metamaterial geometries to constituent materials that change electromagnetic properties under specific environmental stimuli. This paper presents a survey of the development of reconfigurable and tunable metamaterial technology as well as of the applications where such capabilities are valuable.
    Preview · Article · May 2014 · International Journal of Antennas and Propagation
  • Jeremy A Bossard · Lan Lin · Seokho Yun · Liu Liu · Douglas H Werner · Theresa S Mayer
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    ABSTRACT: Nanostructured optical coatings with tailored spectral absorption properties are of interest for a wide range of applications such as spectroscopy, emissivity control, and solar energy harvesting. Optical metamaterial absorbers have been demonstrated with a variety of customized single band, multiple band, polarization, and angular configurations. However, metamaterials that provide near unity ab-sorptivity with super-octave bandwidth over a specified optical wavelength range have not yet been demonstrated experimentally. Here, we show a broadband, polarization-insensitive metamaterial with greater than 98% measured average absorptivity that is maintained over a wide ±45º field-of-view for mid-infrared wavelengths between 1.77 and 4.81 µm. The nearly ideal absorption is realized by using a genetic algorithm to identify the geometry of a single-layer metal nanostructure array that excites multiple overlapping electric resonances with high optical loss across greater than an octave band-width. The response is optimized by substituting palladium for gold to increase the infrared metallic loss and by introducing a dielectric superstrate to suppress reflection over the entire band. This demonstration advances the state-of-the-art in high-performance broadband metamaterial absorbers that can be reliably fabricated using a single patterned layer of metal nanostructures.
    No preview · Article · Jan 2014 · ACS Nano
  • Zhi Hao Jiang · Lan Lin · Jeremy A Bossard · Douglas H Werner
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    ABSTRACT: In this work, we present the design, numerical experiments, and analysis of a plasmonic metamaterial thin film based on subwavelength nano-notch loaded modified fishnet structures. The resulting device offers a simultaneous bandpass filtering functionality with a broad enhanced optical transmission window and a gapless negative-zero-positive index transition to enable polarization-independent passive beam-steering. This unique characteristic is made possible by the introduced subwavelength nano-notches, which provide fine tuning and hybridization of the external and internal surface plasmon polariton modes. This allows tailoring of the dispersive properties of the plasmonic metamaterial for broadband operation. Specifically, a multilayer nanostructured modified fishnet with feature sizes accessible by modern nanofabrication techniques is presented, exhibiting a broad passband at the mid-infrared wavelengths from 3.0 to 3.7 µm and stopbands elsewhere in the 2.5 ~4.5 µm window. The transmittance normalized to area is around 3 dB within the broad 20% bandwidth of the passband. Additionally, the effective index undergoes a smooth transition from negative unity through zero to positive unity with low loss within the passband. The physical mechanism and the angular dispersion of the metamaterial are analyzed in detail. Finally, full-wave simulations of a prism formed from this metamaterial are performed to demonstrate that the proposed structure achieves simultaneous polarization-insensitive passive beam-steering and filtering functionalities.
    No preview · Article · Dec 2013 · Optics Express
  • Jason A. Ashbach · Jeremy A. Bossard · Xiande Wang · Douglas H. Werner
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    ABSTRACT: Infrared (IR) absorbers have been previously studied for use in narrow-band and multi-band applications. Here, we investigate a novel absorber structure based on an electromagnetic band-gap (EBG) metasurface with a curvilinear metallic screen. CMA-ES was employed to determine the coefficients used in the screen generation in order to successfully design an absorber for the near-IR.
    No preview · Conference Paper · Jul 2013
  • Jeremy A. Bossard · Douglas H. Werner
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    ABSTRACT: Metamaterial coatings have been previously studied for their ability to tailor the dispersive IR emissivity of a surface. Here, we investigate metamaterial structures based on an electromagnetic band-gap surface for use as near-IR emitters with custom angle and polarization selectivity. A genetic algorithm is successfully employed to optimize the metamaterial structures to have minimum emissivity in the normal direction and high emissivity at desired off-normal angles with custom polarization.
    No preview · Conference Paper · Jul 2013
  • Jeremy A. Bossard · Lan Lin · Seokho Yun · Douglas H. Werner · Theresa S. Mayer
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    ABSTRACT: Infrared (IR) absorbers have been previously studied for use in narrow-band, multi-band, and broadband applications. Here, we investigate through synthesis and experiment a broadband absorber structure based on an electromagnetic band-gap type of metasurface. A genetic algorithm is successfully employed to optimize a structure with a single patterned Pd screen to exhibit high absorptivity over more than an octave bandwidth across the mid-IR regime.
    No preview · Conference Paper · Jul 2013
  • Jeremy A. Bossard · Jeremiah P. Turpin · Douglas H. Werner
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    ABSTRACT: Metamaterials have been previously studied for their ability to tailor the IR emissivity dispersion, pattern, and polarization of a surface. Here, we investigate a reconfigurable metamaterial structure based on dielectric resonators composed of phase-change material for use as near-IR emitters with custom angle selectivity. A genetic algorithm is successfully employed to optimize the metamaterial structures to have minimum emissivity in the normal direction and high emissivity at desired off-normal angles specified by the designer.
    No preview · Conference Paper · Jul 2013
  • Zikri Bayraktar · Muge Komurcu · Jeremy A. Bossard · Douglas H. Werner
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    ABSTRACT: A new type of nature-inspired global optimization methodology based on atmospheric motion is introduced. The proposed Wind Driven Optimization (WDO) technique is a population based iterative heuristic global optimization algorithm for multi-dimensional and multi-modal problems with the potential to implement constraints on the search domain. At its core, a population of infinitesimally small air parcels navigates over an N-dimensional search space following Newton's second law of motion, which is also used to describe the motion of air parcels within the earth's atmosphere. Compared to similar particle based algorithms, WDO employs additional terms in the velocity update equation (e.g., gravitation and Coriolis forces), providing robustness and extra degrees of freedom to fine tune. Along with the theory and terminology of WDO, a numerical study for tuning the WDO parameters is presented. WDO is further applied to three electromagnetics optimization problems, including the synthesis of a linear antenna array, a double-sided artificial magnetic conductor for WiFi applications, and an E-shaped microstrip patch antenna. These examples suggest that WDO can, in some cases, out-perform other well-known techniques such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA) or Differential Evolution (DE) and that WDO is well-suited for problems with both discrete and continuous-valued parameters.
    No preview · Article · May 2013 · IEEE Transactions on Antennas and Propagation
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    ABSTRACT: Metamaterials have the potential to create optical devices with new and diverse functionalities based on novel wave phenomena. Most practical optical systems require that the device properties be tightly controlled over a broad wavelength range. However, optical metamaterials are inherently dispersive, which limits operational bandwidths and leads to high absorption losses. Here, we show that deep-subwavelength inclusions can controllably tailor the dispersive properties of an established metamaterial structure thereby producing a broadband low-loss optical device with a desired response. We experimentally verify this by optimizing an array of nano-notch inclusions, which perturb the mode patterns and strength of the primary and secondary fishnet nanostructure resonances and give an optically thin mid-wave-infrared filter with a broad transmissive pass-band and near-constant group delay. This work outlines a powerful new strategy for realizing a wide range of broadband optical devices that exploit the unique properties of metamaterials.
    Preview · Article · Mar 2013 · Scientific Reports
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    Jeremy A Bossard · Douglas H Werner
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    ABSTRACT: Metamaterials have been previously studied for their ability to tailor the dispersive IR emissivity of a surface. Here, we investigate two metamaterial structures based on an electromagnetic band-gap surface and a dielectric resonator array for use as near-IR emitters with custom angle selectivity. A genetic algorithm is successfully employed to optimize the metamaterial structures to have minimum emissivity in the normal direction and high emissivity at custom off-normal angles specified by the designer. Two symmetry conditions are utilized to achieve emissivity patterns that are azimuthally stable or distinct in the two orthogonal plane cuts.
    Preview · Article · Mar 2013 · Optics Express
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    Jeremy A Bossard · Douglas H Werner
    [Show abstract] [Hide abstract]
    ABSTRACT: Metamaterials have been previously studied for their ability to tailor the dispersive infrared (IR) emissivity of a surface. Here, we investigate metamaterial coatings based on an electromagnetic band-gap surface for use as near-IR emitters with custom polarization selectivity. A genetic algorithm is successfully employed to optimize the metamaterial structures to exhibit custom linear, circular, and elliptical polarization. A study is also conducted on a bi-anisotropic slab, showing that anisotropic chirality is required in the metamaterial structure in order to achieve circular or elliptical emissivity polarization.
    Preview · Article · Feb 2013 · Optics Express
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    ABSTRACT: This chapter considers a class of optimization techniques that were developed to imitate processes found in nature. Nature is a wonderful source of inspiration for global optimization because so many aspects of natural phenomenon can be mimicked and employed for solving challenging design problems, from the very process of evolution to the coordinated search behavior of various swarming organisms. Nature inspired search algorithms have played an important role in electromagnetic design, as they have proven to be very robust at solving complex problems with many design parameters. Also, as the field of metamaterials has developed, optimization has become an important tool in the quest to overcome performance limitations such as high loss and narrow bandwidth, which have limited the widespread use of metamaterials in practical device applications. In the first part of this chapter, three prominent nature inspired optimization algorithms are described in detail, including the genetic algorithm (GA), particle swarm optimization (PSO), and the covariance matrix adaptation evolutionary strategy (CMA-ES). Following this, several examples of metamaterial surfaces are presented that have each been optimized by one of the three nature inspired techniques. Finally, two homogenization techniques that can be employed to invert scattering parameters for a slab of metamaterial to obtain isotropic or anisotropic effective medium parameters are examined and used in conjunction with a GA to overcome previous limitations in terms of loss and angular stability in metamaterials.
    No preview · Chapter · Jan 2013
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    ABSTRACT: Graphene, which has a linear electronic band structure, is widely considered as a semimetal. In the present study, we combine graphene with conventional metallic surface-enhanced Raman scattering (SERS) substrates to achieve higher sensitivity of SERS detection. We synthesize high-quality, single-layer graphene sheets by chemical vapor deposition (CVD) and transfer them from copper foils to gold nanostructures, i.e., nanoparticle or nanohole arrays. SERS measurements are carried out on methylene blue (MB) molecules. The combined graphene nanostructure substrates show about threefold or ninefold enhancement in the Raman signal of MB, compared with the bare nanohole or nanoparticle substrates, respectively. The difference in the enhancement factors is explained by the different morphologies of graphene on the two substrates with the aid of numerical simulations. Our study indicates that applying graphene to SERS substrates can be an effective way to improve the sensitivity of conventional metallic SERS substrates.
    Preview · Article · Apr 2012 · The Journal of Physical Chemistry C
  • Zikri Bayraktar · Jeremy A. Bossard · Xiande Wang · Douglas H. Werner
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    ABSTRACT: A parallelized real-valued clonal selection algorithm (CLONALG) is successfully implemented in this paper utilizing message passing interface (MPI) to reduce the computational burden of a large clone pool. CLONALG is one of the many branches of Artificial Immune System (AIS) algorithms with unique inherent properties that make it a very efficient optimization techniques for multimodal problems such as the ones commonly encountered in computational electromagnetic design. As a demonstration of its effectiveness, a numerical study is carried out with known benchmark functions along with the optimization of multi-layered frequency selective surface (FSS) filters in the X-band. Our results show that the CLONALG can consistently outperform a standard GA implementation particularly in multi-modal optimization problems.
    No preview · Article · Apr 2012 · IEEE Transactions on Antennas and Propagation
  • J.A. Bossard · D.H. Werner
    [Show abstract] [Hide abstract]
    ABSTRACT: Metamaterials have been previously studied for their ability to tailor the dispersive IR emissivity of a surface. Here, we investigate two metamaterial structures based on an electromagnetic band-gap surface and dielectric resonators for use as near-IR emitters with custom angle selectivity. A genetic algorithm is successfully employed to optimize the metamaterial structures to have minimum emissivity in the normal direction and high emissivity at desired off-normal angles specified by the designer.
    No preview · Conference Paper · Jan 2012
  • J.A. Bossard · D.H. Werner
    [Show abstract] [Hide abstract]
    ABSTRACT: Metamaterials have been previously studied for their ability to tailor the dispersive IR emissivity of a surface. Here, we investigate a metamaterial structure based on an electromagnetic band-gap surface for use as near-IR emitters with custom polarization selectivity. A genetic algorithm is successfully employed to optimize a metamaterial structure to exhibit maximum circularly polarized emissivity in the normal direction.
    No preview · Conference Paper · Jan 2012
  • J.A. Bossard · Z. Bayraktar · D.H. Werner
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    ABSTRACT: Infrared (IR) absorbers have been previously studied for use in narrow-band and multi-band applications. Here, we investigate a broadband absorber structure comprised of multiple, stacked frequency selective surface screens. A genetic algorithm is successfully employed to optimize a structure with three Au screens to exhibit high absorptivity across the mid-IR range from 3 μm to 5 μm.
    No preview · Conference Paper · Jan 2012