We designed a metamaterial field rotator that can rotate electromagnetic wave fronts. Our starting point was the transformation-media concept. Effective medium theories and full simulations facilitated actual design process. created at very simple structure comprising of an array identical aluminum metal plates. made measured sample we experimentally demonstrated rotation effect as well broadband functionality microwave frequencies.

We study the edge states in two-dimensional photonic crystals arising from a singular point $k$ space at which two dispersion surfaces intersect. The zigzag honeycomb lattice for TM polarization are analogous to electronic ones graphene nanoribbons. Electromagnetic modes edges of such consisting ferrite rods allowed propagate only along one direction. one-way propagation is insensitive imperfections on edge.

Highy crystalline NiO nanoparticles are uniformly grown on the walls of carbon nanotubes (CNTs) by atomic layer deposition (ALD) at moderate temperature.Their size and stoichiometry controlled ALD process parameters. The obtained NiO/CNT hybrids exhibit excellent performance in electro-oxidation methanol.

Negatively and positively refractive behaviors are achieved in a two-dimensional photonic crystal of pillar type for TE TM polarizations, respectively, at the same frequency. The is formed by triangular lattice silicon pillars finite height on substrate. A polarization beam splitter based such photonic-crystal slab demonstrated. Measurements near infrared wavelengths indicate that two beams different polarizations can be split with an extinction ratio over 10dB wide wavelength range.

A kind of two-dimensional acoustic metamaterial is designed so that it exhibits strong anisotropy along two orthogonal directions. Based on the rectangular equal frequency contour this metamaterial, magnifying lenses for waves, analogous to electromagnetic hyperlenses demonstrated recently in optical regime, can be realized. Such may offer applications imaging systems obey scalar wave equations.

This paper describes a reconfigurable metalens system that can image at visible wavelengths based on arrays of coupled plasmonic nanoparticles. These lenses manipulated the wavefront and focused light by exciting surface lattice resonances were tuned patterned polymer blocks single-particle sites. Predictive design dielectric nanoblocks was performed using an evolutionary algorithm to create range three-dimensional focusing responses. For scalability, we demonstrated simple technique for...

Abstract This work reports the second‐harmonic generation (SHG) in a z ‐cut thin‐film lithium niobate (LN) under nearly normal‐incident linearly‐polarized pumping. To utilize largest nonlinear term which is along out‐of‐plane direction LN film, film patterned with 2D periodic array to support symmetry‐protected bound states continuum (BICs) bearing strong electric field component. Enabled by such optical resonances near BIC condition at pumping wavelength, significant enhancement SHG...

Spatially extended bound states in the continuum (BICs) can provide high-quality optical feedback for vortex lasing. This work reports that three out of four supported BIC modes 2D square lattices dye-covered TiO2 nanoparticles lase simultaneously under pulsed pumping, while remaining one be tuned into gain bandwidth by adjusting nanoparticle size. All in-plane symmetric exhibited doughnut-shaped lasing patterns, regardless pump polarization, but with a polarization-dependent threshold....

In order to assess the potential of porous Si as thermoelectric material we have performed thermal conductivity measurements in dependence both temperature and average structure size. Investigations on samples with sizes between 7 nm 100 reveal a pronounced reduction which is encouraging for future use material. The observed size can be explained terms simple kinetic model based effective phonon mean free path.

Macroporous silicon with multiscale texture for reflection suppression and light trapping was achieved through a controllable electrochemical etching process. It coated TiO2 by atomic layer deposition, used as the photoanode in photocatalytic water splitting. A conformal pn-junction also built-in order to split without external bias. 45% enhancement photocurrent density observed after black etching. In comparison nano-structured silicon, process here has neither metal contamination nor...

This paper reports how a hybrid system composed of transparent dielectric lattices over metal mirror can produce high-quality lattice resonances for unidirectional lasing. The enhanced electromagnetic fields are concentrated in the cladding periodic structures and away from metal. Based on mirror-image model, we reveal that such governed by bound states continuum resulting destructive interference. Using hexagonal arrays titanium dioxide nanoparticles silica-coated silver mirror, observed...

This paper compares plasmon nanolasing and corresponding ultrafast dynamics supported by Al Au nanoparticle arrays. By tuning size, we achieved high-quality surface lattice resonances from both dipolar plasmons hybrid quadrupolar at near-infrared wavelengths. We demonstrated that the modes can serve as optical feedback for plasmonic nanolasing. Even wavelength of its interband transition, showed properties similar to Au. Also, independent type cavity mode used feedback, lasing thresholds

Abstract This article reports refractometric sensing using two optical resonances of different types supported by TiO 2 nanopillar arrays on a gold film, which can be exposed to aqueous or organic environments. One lattice resonance, with enhanced electric fields extending into the surrounding environment, maintain quality factor Q > 200 when bulk refractive index environment varies in large range from 1.33 1.58. resonance exhibits not only sharp transitions reflected light intensity but...

A two-dimensional metallo-dielectric photonic crystal of negative refraction was designed for the application polarization beam splitters. To match refractive index air, effective is ?1 TE and +1 TM polarization. Two types splitter are presented.

This paper reports dual-mode vortex lasing with a topological charge of −2 via doubly degenerate bound states in the continuum. We patterned photonic crystal slab hexagonal TiO2 nanoparticles arranged lattice to support continuum at Γ point, and finite array was truncated have square boundary. Because emission from point is forbidden, emerges off-Γ points, where double degeneracy lifted, resulting two peaks close wavelength. The coherence time about 1.4 ps under pulsed pumping width 75 fs....

This paper reports how a simple plasmonic lattice, containing only one metal nanoparticle in the unit cell, can produce lasing beams with various polarization patterns. Using arrays of aluminum nanoparticles covered dye solutions, we demonstrated topologically trivial and nontrivial near-infrared regime under nanosecond-pulsed optical pumping. Although exhibit high Ohmic losses, emissions showed narrow line widths below 0.05 nm long coherence time hundreds picoseconds. By comparing...

Entropy engineering has been demonstrated to be an effective strategy regulate the thermoelectric properties of materials. In this work, we report a series single-phase cubic (La0.25Sr0.25Ba0.25Ca0.25)CoO3 (LSBC), (La0.25Nd0.25Sr0.25Ba0.25)CoO3 (LNSB), and (La0.2Nd0.2Sr0.2Ba0.2Ca0.2)CoO3 (LNSBC) ceramics based on high-entropy design in Re site perovskite RECoO3. Electron microscopy results indicate that three samples have high crystallinity exhibit clear pore structure with rich lattice...

Lithographically defined microporous templates in conjunction with the atomic layer deposition (ALD) technique enable remarkable control of complex novel nested nanotube structures. So far three-dimensional physical process parameters has not been fully realized high precision resolution, and requires optimization order to achieve a wider range potential applications. Furthermore, combination composite insulating oxide layers alternating semiconducting metals can provide various types...

We examine the complex band structures and effective medium descriptions of a periodic acoustic composite system. It is shown that if system exhibits negative velocity band, assignment as phononic crystal or ``double negative'' metamaterial unambiguous only in some cases. An example given where properties can be tuned gradually continuously from an to crystal, there no sharp dividing line between these two regimes.

Absorbers for visible and near-infrared light are realized by depositing a thin iron layer on arrays of cones which replicated from porous template. The conic structure itself is several micrometers ineffective at antireflection, but the subsequent deposition top generates nano­meter-size columnar structures, thus broadband absorption enhancement achieved.

Rutile nanorods are grown on the anatase nanotubes to enhance photocurrent density in photocatalytic water splitting.