Ultrahigh-reflectivity chiral mirrors based on the metasurface of the quarter-waveplate.

A study is conducted on a GaAs-based high-contrast subwavelength chiral metasurface (HCCM) designed for 1064 nm. The metasurface integrates a high-contrast subwavelength grating (HCG) for TM mode modulation, a SiO support layer, and a compact quarter-waveplate (QWP) to convert linearly polarized light to circularly polarized light. The HCG achieves ultra-high reflectivity at 1064 nm, attributed to the large refractive index contrast between the Si grating and SiO2 layer.

Strain- and Electron Doping-Induced In-Plane Spin Orientation at Room Temperature in Single-Layer CrTe.

Ferromagnets with a Curie temperature surpassing room temperature (RT) are highly sought after for advancing planar spintronics. The ultrathin CrTe is proposed as a promising two-dimensional (2D) ferromagnet with a Curie temperature above 300 K. However, its single-layer film is highly susceptible to specific external perturbations, leading to variable magnetic features depending on the environment.

Full-Stokes polarization photodetector based on the hexagonal lattice chiral metasurface.

A hexagonal lattice silicon (Si) metasurface formed by the displacement of two mirrored isosceles trapezoid blocks in opposite directions is integrated into an InGaAs/InP photodetector to sense the circularly polarized light, whose optical properties mainly are controlled by the Fabry-Pérot (FP) cavity mode supported in the air slit called the Tunnel A. The Si metasurface can also be equivalent to the combination of the electric quadrupole (EQ) and the magnetic quadrupole (MQ) for the right circularly polarized (RCP) mode and the magnetic quadrupole for the left circularly polarized (LCP) mode. The external quantum efficiency of the circular polarization photodetectors is 0.

The Ultra-Large-Bandwidth Cascade Full-Stokes-Imaging Metasurface Based on the Dual-Major-Axis Circular Dichroism Grating.

A dual-major-axis grating composed of two metal-insulator-metal (MIM) waveguides with different dielectric layer thicknesses is numerically proposed to achieve the function of the quarter-wave plate with an extremely large bandwidth (1.0-2.2 μm), whose optical properties can be controlled by the Fabry-Pérot (FP) resonance.

Switchable trifunctional terahertz absorber for both broadband and narrowband operations.

In this paper, we proposed a multilayer terahertz absorber composed of hybrid graphene and vanadium dioxide (VO2). Based on electrical controlling of graphene and thermal tuning of VO2, three different switchable absorption states are achieved in one structure. When VO2 is in the metal phase and the Fermi level of graphene is set as 0eV, high-frequency broadband (bandwidth, 5.

Mutual coupling of corner-localized quasi-BICs in high-order topological PhCs and sensing applications.

Recently, high-order topological photonic crystals (PhCs) have attracted huge research attention due to their novel physics mechanism and the application potential in integrated photonics. Based on the two-dimensional Su-Schrieffer-Heeger model, we construct and study the mutual coupling between the high-order corner states in 2D dielectric PhCs. Simulation results show that the Q-factor of such corner-localized quasi-bound states in the continuum (BICs) could be enhanced following mutual coupling in finite size.

Mid-Infrared Sensor Based on Dirac Semimetal Coupling Structure.

A multilayer structure based on Dirac semimetals is investigated, where long-range surface plasmon resonance (LRSPR) of a dielectric layer/Dirac semimetal/dielectric layer are coupled with surface plasmon polaritons (SPPs) on graphene to substantially improve the Goos−Hänchen (GH) shift of Dirac semimetals in the mid-infrared band. This has important implications for the study of mid-infrared sensors. We studied the reflection coefficient and phase of this multilayer structure using a generalized transport matrix.

Flexible alternating current electroluminescent devices integrated with high voltage triboelectric nanogenerators.

Flexible alternating current electroluminescent (ACEL) devices have attracted growing interest as promising wearable displays for their uniformity of light emission, low power consumption, and excellent reliability. However, the requirement of high-voltage power sources for driving ACEL devices greatly impedes their portability and commercialization. Here, we developed flexible ACEL devices integrated with high output-voltage triboelectric nanogenerators (TENG) using easy and low-cost crumpled Al electrodes.

Large bandwidth and high-efficiency plasmonic quarter-wave plate.

A large bandwidth and high-efficiency subwavelength quarter-wave plate (QWP) is an indispensable component of an integrated miniaturized optical system. The bandwidth of existing plasmonic quarter-wave plates with a transmission efficiency of more than 50% is less than 320 nm in the near-infrared band. In this paper, a metallic quarter-wave plate with a bandwidth of 600 nm (0.

Polarization-Selective Bidirectional Absorption Based on a Bilayer Plasmonic Metasurface.

We propose an alignment-free and polarization-selective bidirectional absorber composed of a one-dimensional bilayer Au grating array buried in a silicon nitride spacer. The absorptivity of the designed structure is more than 95% (77%) under normal forward (backward) TM-polarized light incidence, and is more than 80% (70%) within a forward (backward) incident angle up to 30°. The great bidirectional absorption performance is illustrated by the resonance coupling of the surface plasmon polaritons (SPPs) resonance, the propagating surface plasmon (PSP) resonance and the localized surface plasmon (LSP) resonance under TM-polarized wave illumination.

Full-Stokes imaging polarimetry based on a metallic metasurface.

We use a single-layer thick metallic metasurface to design the 0-,45- and 90-degree polarizers with transmission efficiencies exceeding 95% based on the bright electric dipole resonance and dark magnetic dipole resonance. In addition, we utilize a bilayer metallic metasurface (forming an efficient Fabry-Perot resonator) to propose a circularly polarizing dichroism waveplate (CPDW). The circular polarization dichroism (CPD = I - I.

Self-Powered Flexible Blood Oxygen Monitoring System Based on a Triboelectric Nanogenerator.

Flexible optoelectronics based on inorganic functional components have attracted worldwide attention due to their inherent advantages. However, the power supply problem presents a significant obstacle to the commercialization of wearable optoelectronics. Triboelectric nanogenerator (TENG) technology has the potential to realize self-powered applications compared to the conventional charging technologies.

Theoretical System of Contact-Mode Triboelectric Nanogenerators for High Energy Conversion Efficiency.

As the rapid expansion of next-generation electronics, portable and efficient energy sources has become one of the most important factors impeding the market development. Triboelectric nanogenerators (TENGs) are a potential candidate for its unsurpassed features. Herein, we deeply analyzed the power and conversion efficiency of contact-mode TENGs considering the whole energy conversion process.

A fully verified theoretical analysis of strain-photonic coupling for quantum wells embedded in wavy nanoribbons.

For optoelectronic devices, an attractive research field involves the flexible adjustment of the band gap in semiconductor quantum well (QW) structures by strain engineering. However, rigid wafer-based technology enables lattice-misfit strain during epitaxial growth, which is biaxial, unchangeable, and not sufficient for the devices fitted on various irregular surfaces. Therefore, exploiting the strain produced by externally deformed configurations offers unique opportunities to continuously and non-defectively tune the QW's band structure.

Metallic metasurfaces for high efficient polarization conversion control in transmission mode.

A high efficient broadband polarization converter is an important component in integrated miniaturized optical systems, but its performances is often restricted by the material structures, metallic metasurfaces for polarization control in transmission mode never achieved efficiency above 0.5. Herein, we theoretically demonstrate that metallic metasurfaces constructed by thick cross-shaped particles can realize a high efficient polarization transformation over a broadband.

Epidermal Inorganic Optoelectronics for Blood Oxygen Measurement.

Flexible and stretchable optoelectronics, built-in inorganic semiconductor materials, offer a wide range of unprecedented opportunities and will redefine the conventional rigid optoelectronics in biological application and medical measurement. However, a significant bottleneck lies in the brittleness nature of rigid semiconductor materials and the performance's extreme sensitivity to the light intensity variation due to human skin deformation while measuring physical parameters. In this study, the authors demonstrate a systematic strategy to design an epidermal inorganic optoelectronic device by using specific strain-isolation design, nanodiamond thinning, and hybrid transfer printing.

Buckling-Based Method for Measuring the Strain-Photonic Coupling Effect of GaAs Nanoribbons.

The ability to continuously and reversibly tune the band gap and the strain-photonic coupling effect in optoelectronic materials is highly desirable for fundamentally understanding the mechanism of strain engineering and its applications in semiconductors. However, optoelectronic materials (i.e.

Active metasurface terahertz deflector with phase discontinuities.

Metasurfaces provide great flexibility in tailoring light beams and reveal unprecedented prospects on novel functional components. However, techniques to dynamically control and manipulate the properties of metasurfaces are lagging behind. Here, for the first time to our knowledge, we present an active wave deflector made from a metasurface with phase discontinuities.

Tunable plasmon-induced transparency in hybrid waveguide-magnetic resonance system.

We present a hybrid waveguide-magnetic resonance system with split ring resonators (SRRs) periodically arranged on top of a waveguide layer. Due to the destructive interference between the electric coupling to the magnetic resonance mode generated in the SRRs and the TE/TM waveguide modes supported by the waveguide layer, double plasmon-induced transparency is obtained at the infrared wavelength. Furthermore, the PIT resonance can be dynamically tuned by the incident angle.

Tunable coupling-induced transparency band due to coupled localized electric resonance and quasiguided photonic mode in hybrid plasmonic system.

A numerical and theoretical study is presented on the exhibition of tunable narrow band coupled-induced transparency phenomenon in a hybrid waveguide-plasmon system consisting of gold twin nanowires array embedded in a slab waveguide. We show that, at slightly non-normal incidence, a properly designed splitting of transmission with narrow transparency peaks may occur at a given wavelength, depending on the angle of incidence. This leads to the wavelength-selective high quality coupled-induced transparency resonance at optical frequencies.

Hybrid plasmonic waveguide with gain medium for lossless propagation with nanoscale confinement.

In this Letter, we propose a hybrid plasmonic nanosystem consisting of a silver cladding layer with a semicylinder bump on top of InGaAsP nanowire. Because of the coupling between the dielectric waveguide mode and surface plasmon polariton mode, the hybrid plasmonic mode can exhibit low loss with strong field localization. The finite element method numerical simulations are employed to evaluate the performances of the hybrid mode.

Broadband short-range surface plasmon structures for absorption enhancement in organic photovoltaics.

We theoretically demonstrate a polarization-independent nanopatterned ultra-thin metallic structure supporting short-range surface plasmon polariton (SRSPP) modes to improve the performance of organic solar cells. The physical mechanism and the mode distribution of the SRSPP excited in the cell device were analyzed, and reveal that the SRSPP-assisted broadband absorption enhancement peak could be tuned by tailoring the parameters of the nanopatterned metallic structure. Three-dimensional finite-difference time domain calculations show that this plasmonic structure can enhance the optical absorption of polymer-based photovoltaics by 39% to 112%, depending on the nature of the active layer (corresponding to an enhancement in short-circuit current density by 47% to 130%).

Hybrid waveguide-plasmon resonances in gold pillar arrays on top of a dielectric waveguide.

We propose a hybrid waveguide-plasmon system consisting of gold pillar arrays on top of a dielectric waveguide. The formation of extraordinary transmissions induced by the hybrid waveguide-plasmon resonances is investigated by rigorous coupled-wave analysis. The characteristics of the hybrid resonances can be predicted by introducing the photonic crystal slab theory.