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Bound states in the continuum and Fano resonances in subwavelength resonator arrays
(2021)SAM Research ReportWhen wave scattering systems are subject to certain symmetries, resonant states may decouple from the far-field continuum; they remain localized to the structure and cannot be excited by incident waves from the far field. In this work, we use layer-potential techniques to prove the existence of such states, known as bound states in the continuum, in systems of subwavelength resonators. When the symmetry is slightly broken, this resonant ...Report -
Fast Magnetic Resonance Electrical Impedance Tomography with highly undersampled data
(2016)Research ReportReport -
Quantitative estimates for stress concentration of the Stokes flow between adjacent circular cylinders
(2020)SAM Research ReportWhen two inclusions with high contrast material properties are located close to each other in a homogeneous medium, stress may become arbitrarily large in the narrow region between them. In this paper, we investigate such stress concentration in the two-dimensional Stokes flow when inclusions are the two-dimensional cross sections of circular cylinders of the same radii and the background velocity field is linear. We construct two ...Report -
Exceptional points in parity-time-symmetric subwavelength metamaterials
(2020)SAM Research ReportWhen sources of energy gain and loss are introduced to a wave scattering system, the underlying mathematical formulation will be non-Hermitian. This paves the way for the existence of exceptional points, whereby eigenmodes are linearly dependent. The main goal of this work is to study the existence and consequences of exceptional points in the setting of high-contrast subwavelength metamaterials. We begin by studying a system of two ...Report -
Identification of an algebraic domain in two dimensions from a finite number of its generalized polarization tensors
(2018)SAM Research ReportReport -
Shape and size dependence of dipolar plasmonic resonance of nanoparticles
(2018)SAM Research ReportReport -
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The point-interaction approximation for the fields generated by contrasted bubbles at arbitrary fixed frequencies
(2018)SAM Research ReportReport -
A biomimetic basis for the perception of natural sounds
(2020)SAM Research ReportArrays of subwavelength resonators can mimic the biomechanical properties of the cochlea, at the same scale. We derive, from first principles, a modal time-domain expansion for the scattered pressure field due to such a structure and propose that these modes should form the basis of a signal processing architecture. We investigate the properties of such an approach and show that higher-order gammatone filters appear by cascading. Further, ...Report -
A direct linear inversion for discontinuous elastic parameters recovery from internal displacement information only
(2018)SAM Research ReportReport