Man-made structural colors, which originate from resonant interactions between visible light and manufactured nanostructures, are emerging as a solution for ink-free color printing. We show that non-iridescent colors can be conveniently produced by nanostructures made high-index dielectric materials. Compared to plasmonic analogs, surfaces with dielectrics, such germanium (Ge), have lower reflectance, yielding superior contrast. Taking advantage of band-to-band absorption in Ge, we...

A zero index metamaterial (ZIM) can be utilized to block wave (super-reflection) or conceal objects completely (cloaking). The "super-reflection" device is realized by a ZIM with perfect electric (magnetic) conductor inclusion of arbitrary shape and size for transverse incident wave. In contrast, magnetic (electric) used shape. underlying physics here determined the intrinsic properties ZIM.

A high efficiency surface plasmonic coupler composed of a tapered silicon strip waveguide and subwavelength scale metal gap is experimentally demonstrated. By tuning the parameters taper gap, theoretical coupling efficiencies can be as 88% for wide wavelength range. silicon-gold then fabricated, demonstrating 35% per facet. Our experimental demonstration crucial step hybrid integration components with conventional dielectric components.

We investigate the performance of bends and splitters in graphene nanoribbon waveguides.Although waveguides are lossy themselves, we show that do not induce any additional loss provided width is sub-wavelength.We use transmission line theory to qualitatively interpret behavior observed our simulation.Our results pave a promising way realize ultra-compact devices operating terahertz region.

We experimentally demonstrate graphene-plasmon polariton excitation in a continuous graphene monolayer resting on two-dimensional subwavelength silicon grating. The grating is fabricated by nanosphere lithography technique with self-assembled array as template. Measured transmission spectra illustrate the of polaritons, which further supported numerical simulations and theoretical prediction plasmon-band diagrams. Our grating-assisted coupling to polaritons forms an important platform for...

Nanostructured graphene on SiO2 substrates pave the way for enhanced light-matter interactions and explorations of strong plasmon-phonon hybridization in mid-infrared regime. Unprecedented large-area nanodot antidot optical arrays are fabricated by nanosphere lithography, with structural control down to sub-100 nanometer The interaction between plasmon modes substrate phonons is experimentally demonstrated used map out plasmons phonons, showing coupling energies order 20 meV. Our findings...

We study metamaterials known as hyperbolic media that in the usual local-response approximation exhibit dispersion and an associated broadband singularity density of states. Instead, from more microscopic hydrodynamic Drude theory we derive qualitatively different optical properties these metamaterials, due to free-electron nonlocal response their metal constituents. demonstrate gives rise a large-wavevector cutoff is inversely proportional Fermi velocity electron gas, but also for small...

Inspired by recent measurements on individual metallic nanospheres that cannot be explained with traditional classical electrodynamics, we theoretically investigate the effects of nonlocal response in three distinct settings: atomic spontaneous emission, electron energy loss spectroscopy, and light scattering. These constitute two near-field one far-field measurements, zero-, one-, two-dimensional excitation sources, respectively. We search for clearest signatures hydrodynamic pressure waves...

We investigate the hydrodynamic theory of metals, offering systematic studies linear-response dynamics for an inhomogeneous electron gas. include quantum functional terms Thomas-Fermi kinetic energy, von Weizs\"acker and exchange-correlation Coulomb energies under local density approximation. The advantages, limitations, possible improvements are transparently demonstrated. roles various parameters in identified. anticipate that can be applied to linear response complex metallic...

Cylinder-shaped perfect lens deduced from the coordinate transformation method is proposed. The previously reported slab noticed to be a limiting form of cylindrical when inner radius approaches infinity with respect thickness. Connaturality between and affirmed by comparing their eigenfield transfer functions. We numerically confirm subwavelength focusing capability such consideration material imperfection. Compared lens, has several advantages, including finiteness in cross section ability...

By investigating wave properties at cloak boundaries, invisibility cloaks with arbitrary shape constructed by general coordinate transformations are confirmed to be perfectly invisible the external incident wave. The differences between line transformed and point discussed. fields in medium found analytically related original space via transformation functions. At exterior boundary of cloak, it is shown that no reflection excited even though permittivity permeability do not always have a...

We theoretically examine the role of Kerr nonlinearities for graphene plasmonics in nanostructures, specifically nanoribbons. The nonlinear interaction is included semiclassically intraband approximation. resulting electromagnetic problem solved numerically by self-consistent iteration with linear steps using a real-space discretization. derive simple approximation resonance shifts general and obtain excellent agreement numerics moderately high field strengths. Near plasmonic resonances are...

Abstract We present a novel wave equation for linearized plasmonic response, obtained by combining the coupled real-space differential equations electric field and current density. Nonlocal dynamics are fully accounted for, formulation is very well suited numerical implementation, allowing us to study waveguides with subnanometer cross-sections exhibiting extreme light confinement. show that groove wedge have fundamental lower limit in their mode confinement, only captured nonlocal theory....

We study the blueshift of surface plasmon (SP) resonance energy isolated Ag nanoparticles with decreasing particle diameter, which we recently measured using electron loss spectroscopy (EELS). As diameter decreases from 26 down to 3.5 nm, a large 0.5 eV SP is observed. In this paper, base our theoretical interpretation experimental findings on nonlocal hydrodynamic model, and compare effect substrate approach an effective homogeneous background permittivity. derive polarizability small metal...

We develop a nonlocal-response generalization to the Green's function surface-integral method (GSIM), also known as boundary-element method. This numerically efficient can accurately describe linear hydrodynamic nonlocal response of arbitrarily shaped plasmonic nanowires in arbitrary dielectric backgrounds. All previous general-purpose methods for are bulk methods. expand possible geometries which usual local-response GSIM be applied, by showing how regularize singularities that occur...

Characteristics of surface modes at the interface between an isotropic medium and indefinite that has a dispersion relation hyperbolic form are studied. Four cases for medium, including normal, left-handed, magnetic (with negative permeability), metallic media, considered. The conditions existence in each case analyzed detail, results expressed explicitly, indicating is determined by nature as well orientation boundary this anisotropic medium. energy flows associated with also discussed.

A type of simplified cloaks with matched exterior boundaries is proposed. The cloak uses nonmagnetic material for the TM polarization and can function a relatively thin thickness. It shown that zeroth order scattering such dominant among all cylindrical terms. gap added at cloak’s inner surface to eliminate through mechanism resonance. reduction in smooth, indicating proposed method has good tolerance perturbations. Numerical simulations also confirm structure very low scattering.

We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but larger wavelengths longitudinal pressure waves free-electron plasma metal constituents.We derive corrections to effective material parameters analytically, and illustrate noticeable dispersion curves numerically.As application, we find that characteristics a HMM lens...

Dead-time has a significant influence on the detection efficiency and range performance of photon-counting laser radar system with Geiger-mode avalanche photodiode. In this paper, rapid universal recursive model probability discrete time under various dead-times is proposed, which verified controlled parameters. Our advantage fast computing speed unifies multi-trigger, single-trigger, zero-dead-time models. The 1 to 2 orders magnitude faster than Gatt's Zhao's models short dead-time...

Nihility media in the previous literature are usually understood as with = μ 0. Transformation optics opens a new perspective for capturing essence of such media. From this perspective, we generalize definition nihility transformation derived from volumeless geometrical elements. A elements can be either point (P), line (L), or surface (S). Their corresponding therefore called P-, L-, S-type media, respectively. The defined 0 is special case under P-type constructions by metamaterials...

A low loss optical interconnection between fibers and photonic integrated circuits is critical for high performance systems. In the past decade, spot size converters, subwavelength waveguide grating (SWG) structures, different refractive index materials have been applied to allow efficient coupling fiber chips. However, it still challenging achieve low-loss when interfacing contrast waveguides such as SiN with SMF-28 fibers. this work, we report a multilayer edge-coupler using SiOxN indices...

Plasmons are commonly interpreted with classical electrodynamics, while nonclassical effects may influence the dynamics of plasmon resonances as confinement is approaching few--nanometer scale. However, an unambiguous approach to quantify degree remains. We propose a nonclassical-impact parameter (NCI) characterize from energy perspective, i.e. which fraction total electromagnetic attributed electrodynamic terms and correspondingly be assigned degrees freedom? show that NCI relates directly...

It has been known that, keeping the outer boundary coordinates intact before and after a coordinate transformation is sufficient condition for obtaining reflectionless medium. Here we prove that it also necessary media in an isotropic homogenous background. Our analytical results show of medium must be same as original with combination rotation displacement, which equivalent to situation are kept transformation.

This paper theoretically and experimentally investigates the performance of imaging laser radar (ILR) system under fog condition. Fog is generated controlled homogeneously within a dedicated indoor atmospheric chamber. A physical model reflected pulses due to standard Lambertian target are developed determine width each echo pulse for different concentrations. We show that there good agreement between predicted measured results backscattered return pulses. Based on experimental an empirical...