High-sensitivity refractive index sensor based on strong localized surface plasmon resonance.

This study proposes two types of composite structures based on gold nano circular and nano square rings on a gold thin film for plasmonic refractive index sensing. The finite-difference time-domain method was used for simulation and analysis. The nano square ring composite structure showed superior performance, with five surface plasmon resonance modes, and a peak sensitivity and figure of merit in a liquid environment of 1600 nm/RIU and 86 , respectively.

Intensity controlled and multi-multiplexed full-space achromatic metalens and modulated orbital angular momentum.

The Fabry-Perot (F-P) interference model was used to make a 6-layer metasurface with cross-polarization that can be changed by heat. The fundamental concept behind the metasurface is to utilize the selectivity of linearly polarized waves by a metal grating to achieve broadband and efficient polarized conversion (PC). It also uses the thermal conversion properties of vanadium dioxide (VO) to control the amplitude of terahertz (THz) waves in a dynamic way.

Switchable bi-functional metasurface for absorption and broadband polarization conversion in terahertz band using vanadium dioxide and photosensitive silicon.

We proposed a bi-functional switchable metasurface based on vanadium dioxide (VO) and photosensitive silicon. The metasurface functions as a transmissive polarization converter in its insulating state with asymmetric transmission characteristics. It attains a remarkable polarization conversion rate (PCR) surpassing 90% and a notable maximum asymmetric transmission (AT) parameter value of 0.

Dynamically tunable terahertz quadruple-function absorber based on a hybrid configuration of graphene and vanadium dioxide.

A quadruple-function dynamically tunable terahertz absorber that uses a hybrid configuration of graphene and vanadium dioxide is proposed in this paper. The absorber achieves dynamic conversion of four functions in one structure: ultra-broadband, broadband, single-frequency narrowband and dual-frequency narrowband, by utilizing the electrical control properties of graphene and the phase-shifting properties of vanadium dioxide. Furthermore, the paper also reveals the physical mechanism of the proposed absorber through the electric field distribution and impedance matching theory.

Dual-function tunable metasurface for polarization-insensitive electromagnetic induction transparency and dual-band absorption.

In this paper, we propose a dual-operating mode metasurface based on graphene and vanadium dioxide (VO), which can switch operating modes by changing the temperature. At room temperature (25 °C), the metasurface can generates a polarization-insensitive electromagnetically induced transparency (EIT)-like effect that can be modulated by changing the Fermi energy level () of graphene (through adding external voltage). In addition, the theoretical results derived from the two-particle model are in good agreement with the simulation results based on the finite element method.

Ultra-broadband and completely modulated absorption enhancement of monolayer graphene in a near-infrared region.

Achieving ultra-broadband and completely modulated absorption enhancement of monolayer graphene in near-infrared region is practically important to design graphene-based optoelectronic devices, however, which remains a challenge. In this work, by spectrally designing multiple magnetic plasmon resonance modes in metamaterials to be adjacent to each other, near-infrared light absorption in monolayer graphene is greatly improved to have an averaged absorption efficiency exceeding 50% in a very broad absorption bandwidth of about 800 nm. Moreover, by exerting an external bias voltage on graphene to change Fermi energy of graphene, the ultra-broadband absorption enhancement of monolayer graphene exhibits an excellent tunability, which has a nearly 100% modulation depth and an electrical switching property.

A Tunable Terahertz Metamaterial Absorber Composed of Hourglass-Shaped Graphene Arrays.

In this paper, we demonstrate a tunable periodic hourglass-shaped graphene arrays absorber in the infrared (IR) and terahertz (THz) frequency bands. The effects of graphene geometric parameters, chemical potentials, periods, and incident angles on the pure absorption characteristics are studied by using the Finite Difference Time Domain (FDTD) method. In addition, this paper also analyzes the pure absorption characteristics of bilayer graphene arrays.

Direct Z-scheme CaTiO@BiOBr composite photocatalysts with enhanced photodegradation of dyes.

To efficiently separate photoexcited electron/hole pairs is one of the key points for achieving excellent photocatalysts with high photocatalytic performances. To achieve this aim, here we have assembled CaTiO (CTO) nanoparticles onto BiOBr microplates, thus constructing novel Z-scheme CTO@BiOBr heterojunction composite photocatalysts. Observation by scanning/transmission electron microscopy confirms the good decoration of CTO nanoparticles (15-50 nm) on the surface of BiOBr microplates (diameter 0.

Enhanced photocatalytic performance by hybridization of BiWO nanoparticles with honeycomb-like porous carbon skeleton.

In this work, we have assembled BiWO nanoparticles on the surface of honeycomb-like porous carbon skeleton (PCS) via a hydrothermal route to achieve a new type of PCS@BiWO hybrid composite photocatalysts. The PCS@BiWO hybrid structures are determined by SEM, TEM and XPS characterizations. UV-vis DRS investigation suggests an enhanced visible-light absorption of the PCS@BiWO composites.

Enhanced Photocatalytic Performance and Mechanism of Au@CaTiO Composites with Au Nanoparticles Assembled on CaTiO Nanocuboids.

Using P25 as the titanium source and based on a hydrothermal route, we have synthesized CaTiO nanocuboids (NCs) with the width of 0.3-0.5 μm and length of 0.

Theoretical Investigation of a Highly Sensitive Refractive-Index Sensor Based on TM₀ Waveguide Mode Resonance Excited in an Asymmetric Metal-Cladding Dielectric Waveguide Structure.

This study proposes a highly sensitive refractive-index (RI) sensor based on a TM₀ waveguide mode resonance excited in an asymmetric metal-cladding dielectric waveguide structure, where the analyte serves as the guiding layer. By scanning the wavelength at fixed angles of incidence, the reflection spectra of the sensor were obtained. The results showed that the resonance wavelength redshifted dramatically with increases in the analyte RI, which indicates that this approach can be used to sense both the resonance wavelength and the analyte RI.

Growth Process and CQDs-modified Bi₄Ti₃O Square Plates with Enhanced Photocatalytic Performance.

Bi₄Ti₃O square plates were synthesized via a hydrothermal route, and their growth process was systematically investigated. Carbon quantum dots (CQDs) were prepared using glucose as the carbon source, which were then assembled on the surface of Bi₄Ti₃O square plates via a hydrothermal route with the aim of enhancing the photocatalytic performance. XRD (X-ray powder diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), UV-vis DRS (diffuse reflectance spectroscopy), XPS (X-ray photoelectron spectroscopy), FTIR (Fourier transform infrared spectroscopy), PL (photoluminescence) spectroscopy, EIS (electrochemical impedance spectroscopy) and photocurrent spectroscopy were used to systematically characterize the as-prepared samples.

A novel BiTiO/AgPO heterojunction photocatalyst with enhanced photocatalytic performance.

In this work, we integrated AgPO with BiTiO to form BiTiO/AgPO heterojunction nanocomposites by an ion-exchange method. The as-prepared BiTiO/AgPO composites were systematically characterized by means of XRD, SEM, TEM, BET, XPS, UV-vis DRS, EIS, PL spectroscopy, and photocurrent response. SEM, TEM, and XPS results demonstrate the creation of BiTiO/AgPO heterojunction with obvious interfacial interaction between BiTiO and AgPO.

Effect of Experimental Parameters on the Hydrothermal Synthesis of Bi2WO6 Nanostructures.

Bi2WO6 nanostructures were synthesized by a hydrothermal route, where the effect of various experimental parameters on the products was investigated. It is demonstrated that the sample morphology and size is highly dependent on the NaOH content (or pH value). At C NaOH = 0-0.

Dynamically generating a large-area confined optical field with subwavelength feature size.

By using a prism of high refractive index, free-space cylindrical vector beams can be selectively converted into confined optical fields with large area, such as surface plasmon polaritons or waveguide modes, whose interference will produce optical features at the nanometer scale. Due to the polarization sensitivity of these modes, the macroscopic distribution of the confined field can be dynamically manipulated through an electronically driven liquid crystal. Based on these phenomena, a promising maskless interference nanolithography is proposed and experimentally demonstrated.

Dark-field imaging by active polymer slab waveguide.

A dark-field imaging technique taking advantage of the active polymer slab waveguide (APSW) is experimentally investigated. The dye molecules (Rhodamine 6G, Rh6G) are doped in the polymer film for the launching of surface waves on the APSW, such as the surface plasmon polaritons on the Ag-polymer-air interface, evanescent fields at the polymer-air interface by the total internal reflection, or the guided modes. The localized surface waves will not radiate into the far-field space directly.

Surface-plasmon-coupled emission microscopy with a polarization converter.

Although surface-plasmon-coupled emission-based fluorescence microscopy proves high sensitivity for surface imaging, its donut shape point spread function (PSF) leads to low optical resolution and inefficient signal collection. In this Letter, we experimentally demonstrate the feasibility of solving this problem by the use of a liquid-crystal plate, which could convert the polarization state of surface-plasmon-coupled fluorescence from radial to linear. After being focused by the collection lens, an Airy disk-like PSF of small size can be realized.

[Experimental study of soft X-ray radiation in the interaction of circularly polarized femtosecond-laser-pulse with low pressure xenon].

Using flat-field grating Spectrometer, the ions lines with wavelength between 5 and 60 nm were measured, which were produced by the interaction of circularly polarized 35 femtosecond ultraintense and ultrashort laser-pulse with 5 mm length xenon at the pressure 2 and 3 kPa respectively. The highest transition is the XeVIII: 4d10 5s(2 S1/2)--4d9 5s5p('P3/2) line at wavelength 17.0856 nm at 2 kPa and 3 kPa, the highest transition is 11.

[A measurement of optical emission from the rear surface with solid targets irradiated by ultrashort pulse laser].

The integrated image spectrum and scattering light spectrum of optical emission at normal direction from rear-side of a metallic foil were measured, employing optical CCD camera and OMA optical multi-channel spectrometer. The integrated image spectrum shows that it presents a ring-shape, and in the near margin of the ring-shape a bright localized signal is shown, which is optical transition radiation (OTR) generated by hot electrons transport through solid targets. The scattering spectrum shows that it presents a series of nonperiodic sharp spikes between 300-500 nm, and the sharp spike is ascribed to the coherent transition radiation (CTR) generated by bunches of hot electron beams generated in v x B acceleration mechanism near 400 nm (2 omega).