We present an ultra broadband thin-film infrared absorber made of saw-toothed anisotropic metamaterial. Absorbtivity higher than 95% at normal incidence is supported in a wide range frequencies, where the full absorption width half maximum about 86%. Such property retained well very incident angles too. Light shorter wavelengths are harvested upper parts sawteeth smaller widths, while light longer trapped lower larger tooth widths. This phenomenon explained by slowlight modes metamaterial...

We present the use of Au bowtie nanoantenna arrays (BNAs) for highly efficient, multipurpose particle manipulation with unprecedented low input power and low-numerical aperture (NA) focusing. Optical trapping efficiencies measured are up to 20× conventional high-NA optical traps among highest reported date. Empirically obtained plasmonic "phase diagrams" introduced detail response BNAs as a function power, wavelength, polarization, diameter, BNA array spacing (number density). Using these...

Hexagonal boron nitride (hBN) is a natural hyperbolic material which can also accommodate highly dispersive surface phonon-polariton modes. In this paper, we examine theoretically the mid-infrared optical properties of graphene-hBN heterostructures derived from their coupled plasmon-phonon We found that graphene plasmon couples differently with phonons two Reststrahlen bands, owing to different hyperbolicity. This leads distinctively interaction between an external quantum emitter and modes...

We experimentally demonstrate an infrared broadband absorber for TM polarized light based on array of nanostrip antennas several different sizes. The property is due to the collective effect magnetic responses excited by these nano-antennas at distinct wavelengths. By manipulating differences widths, measured spectra clearly validate our design purpose broadening absorption band. present works very well in a wide angular range.

We demonstrate that the optical response of a single Au bowtie nanoantenna can be favorably modified to increase local intensity by factor 103 in feed gap region when periodic array antennas are used. find periodicity used modulate and shape spectral emission. An analysis emission confirms presence second-harmonic generation two-photon photoluminescence, typical gold nanostructures, but also reveals portion emitted spectrum cannot attributed multiphoton process. Our investigations have...

We study the topological edge plasmon modes between two "diatomic" chains of identical plasmonic nanoparticles.Zak phase for longitudinal in each chain is calculated analytically by solutions macroscopic Maxwell's equations particles quasi-static dipole approximation.This approximation provides a direct analogy with Su-Schrieffer-Heeger model such that eigenvalue mapped to frequency dependent inverse-polarizability nanoparticles.The state found be same as single-particle resonance frequency,...

Few-layer MoS₂nanosheets are homogeneously incorporated in PMMA and show good nonlinear optical responses, suggesting a promising candidate for laser limiting materials.

Topological phononic crystals (PCs) are periodic artificial structures which can support nontrivial acoustic topological bands, and their properties linked to the existence of edge modes. Most previous studies focused on modes in Bragg gaps induced by lattice scatterings. While local resonant would be great use subwavelength control waves, whether it is possible achieve interface states a question. In this article, we study bands near time-reversal symmetric systems elaborate evolution band...

Cathodoluminescence spectroscopy has been performed on silver nanoparticles in a scanning electron microscopy setup. Peaks appearing the visible range for particles fabricated silicon substrate are shown to arrive from excitation of out-of-plane eigenmodes by beam. Monochromatic emission maps have resolve spatial field variation resonant plasmon mode length scale smaller than 25 nm. Finite-difference time-domain numerical simulations both cases light and excitation. The results radiative...

We study the electromagnetic response and surface modes in a generic gapped Dirac material under pumping with circularly polarized light. The valley imbalance due to leads net Berry curvature, giving rise finite transverse conductivity. discuss appearance of nonreciprocal chiral edge modes, their hybridization waveguiding nanoribbon geometry, giant polarization rotation arrays.

We show theoretically that, in the limit of weak dispersion, one-dimensional (1D) binary centrosymmetric photonic crystals can support topological edge modes all band gaps. By analyzing their bulk topology, these "harmonic" be designed a way that they exist at gaps opened center Brillouin Zone, or zone boundaries, both. The results may suggest new approach to achieve robust multi-frequency coupled for applications nonlinear photonics, such as frequency up-conversion.

Light carries angular momentum and as such it can exert torques on material objects. Applications of these opto-mechanical effects were limited initially due to their smallness in magnitude, but later becomes powerful versatile after the invention laser. Novel practical approaches for harvesting light particle rotation have since been demonstrated, where structure is always subjected a positive optical torque along certain axis if incident has projection same axis. We report here an...

The trapped rainbow effect has been mostly found on tapered anisotropic metamaterials (MMs) made of low loss noble metals, such as gold, silver, etc.In this work, we demonstrate that an MM waveguide high metal tungsten can also support the similar to based structure.We show theoretically array tungsten/germanium nano-cones placed top a reflective substrate absorb light at wavelength range from 0.3 μm 9 with average absorption efficiency approaching 98%.It is excitation multiple orders...

In the world of increasing energy consumption, nanogenerators have shown great potential for harvesting and self-powered portable electronics. Herein, a flexible dual-mode triboelectric nanogenerator (TENG) combining both vertical contact-separation single electrical modes has been developed to convert environmental mechanical into electricity using highly encapsulated multifunctional strategies. By introducing polymer melt wetting technique, nanotubes are fabricated on surface TENG, which...

We demonstrate an efficient eigendecomposition method for analyzing the guided modes in metal nanoparticle chains. The proposed has advantage of simultaneously showing dispersion relation and mode quality. It can also separate material properties from geometrical properties. Its efficiency therefore does not depend on complexity polarizability. used to analyze a single pair rigorous dynamic dipole polarizability typically gives redshift compared with results obtained broadly quasi-static...

Chain-like agglomeration (one-dimensional self-assembly) of aqueous gold nanoparticles (NPs) has been experimentally and theoretically studied. It is demonstrated that the chain growth NPs mainly triggered by anisotropic dipolar interaction due to Au−S bonding originating from thiol-ligand capping, plus van der Waals interaction. This self-assembly can be endorsed isotropic electrostatic repulsion between NPs, which finely tuned dielectric constant surrounding media dependent on volume ratio...

We investigate the collective plasmonic modes of metal nanoparticles in periodic two-dimensional (2D) arrays within a point-dipole description. The dynamic dispersion relations 2D are obtained through method which gives an effective polarizability describing response system. Both and mode qualities simultaneously related to imaginary part polarizability, has contributions from single-particle as well interparticle coupling. transverse long-range dipolar interaction is dominated by wave term...

Inspired by recent advancement of ferroelectric-gated memories and transistors, we propose a design nanoplasmonic devices based on graphene sheets clamped in ferroelectric crystals. We show that the two-dimensional plasmons can strongly couple with phonon-polaritons ferroelectrics, leading to characteristic modal wavelength order 100–200 nm at low temperature low-THz frequencies albeit an appreciable dissipation. By patterning ferroelectrics into different domains, one produce compact...

Due to the matching surface energy, WS2 quantum dots (QDs) can be obtained through direct liquid exfoliation in N-methyl-2-pyrrolidone rather than an ethanol and water mixture. Ultra-small QDs with a diameter of 2.4 nm are fabricated by ultrasound method followed high speed centrifugation up 10 000 rpm. An excellent nonlinear optical (NLO) property QD/ polymethylmethacrylate (PMMA) composite for nanosecond pulsed laser at both 532 1064 has been measured. Results illustrate lower onset...

Methods and mechanisms for improvement of photocatalytic activity, are important popular research topics renewable energy production waste water treatment. Here, we demonstrate a facile laser drilling method engineering well-aligned pore arrays on magnetron-sputtered WS

Topological Dirac semimetals made of two-dimensional transition-metal dichalcogenides (TMDCs) have attracted enormous interest for use in electronic and optoelectronic devices because their electron transport properties. As van der Waals materials with a strong interlayer interaction, these are expected to support layer-dependent plasmonic polaritons yet be revealed experimentally. Here, we demonstrate the apparent retardation attenuation mid-infrared (MIR) waves type-II semimetal platinum...

Recent advances in electromagnetic nonreciprocity raise the question of how to engineer nonreciprocal response with geometrical approaches. In this Letter, we examine problem by introducing generalized continua consisting structured points, which carry extra degrees freedom over coordinate transformation. We show that general media have a unique time-varying Riemannian metric structure local spinning components. It is demonstrated can be alternatively identified as torsion tensor...

Robust topological edge modes may evolve into complex-frequency when a physical system becomes non-Hermitian. We show that, while having negligible forward optical extinction cross section, conjugate pair of such complex in non-Hermitian $\mathcal{PT}$-symmetric can give rise to an anomalous sideway scattering they are simultaneously excited by plane wave. propose realization state linear array subwavelength resonators coated with gain media. The prediction is based on analytical two-band...

Nano-composites of two-dimensional atomic layered WS2 and Au nanoparticles (AuNPs) have been fabricated by sulfurization sputtered W films followed immersing into HAuCl4 aqueous solution. The morphology, structure AuNPs distribution characterized electron microscopy. decorated can be more densely formed on the edge defective sites triangle WS2. We compared optical absorption photoluminescence bare Au-decorated layers. Enhancement in is observed Au-WS2 nano-composites, attributed to localized...