A temperature-controlled switching terahertz perfect absorption device based on a VO phase change metamaterial.

In this paper, we design and study a temperature-controlled switchable terahertz perfect absorber based on vanadium dioxide (VO), which shows excellent multi-band performance, high sensitivity and intelligent thermal management. The device consists of four layers in a metal-dielectric composite structure, which are a metal reflection layer, silicon dielectric layer, VO phase change layer and top metal pattern layer from bottom to top. The simulation results show that when VO is in the low-temperature insulation state, the absorption rate of the device is as high as 99.

A multifunctional terahertz device based on vanadium dioxide metamaterials that switches between ultra-broadband absorption and ultra-high- narrowband absorption.

Terahertz (THz) absorbers with ultra-broadband and ultra-narrowband absorption capabilities are crucial for integrated and efficient terahertz modulation. This study proposes a dual-mode tunable terahertz absorber based on the phase transition characteristics of vanadium dioxide (VO), enabling dynamic switching between narrowband and broadband absorption through its insulating-to-metallic transition. In the insulating state, the excitation of quasi-bound states in the continuum (Q-BIC) resonance geometric parameter modulation of silicon pillars is investigated, with its physical mechanism elucidated impedance matching theory and multipole analysis.

Ultra-broadband and ultra-narrowband actively tunable VO metamaterial perfect absorber.

To solve the problems of single absorption function and the complex structure of terahertz absorbers, this study proposes a terahertz (THz) absorber based on vanadium dioxide (VO) driven by electric dipole resonance, which can achieve wideband and narrowband absorption conversion. Simulation results indicate that in the narrowband absorption mode, two narrowband absorption peaks were observed at 14.6 THz and 16.

Narrow-broadband switchable THz absorber based on graphene and VO.

Terahertz waves possess unique electromagnetic properties, such as penetration, high capacity, and non-destructive testing capabilities, making the study of their absorption characteristics highly significant. Building on previous narrowband and broadband research, this paper introduces an absorber capable of switching between narrowband and broadband modes. This absorber leverages the tunability of graphene and the phase transition properties of vanadium dioxide (VO) to achieve adjustable and switchable absorption characteristics.

Photo-thermal induced wide-range and high-precision tunable dispersion turning point in tapered fiber coupler.

A tapered fiber coupler (TFC) whose dispersion turning point (DTP) can be widely and precisely tuned by a 980 nm laser was designed and fabricated in this research. It offers the potential application advantage of adapting to environmental changes while providing both a wide detection range and high sensitivity. Theoretical studies indicate that the operational region near the DTP can achieve an infinitely high sensitivity for refractive index (RI) sensing.

High-temperature-resistant strain sensor based on the asymmetric tapered Fabry-Pérot fiber.

A high-temperature-resistant strain sensor based on an asymmetric tapered Fabry-Pérot fiber (FPI) structure is designed and validated experimentally. The strain sensor is constructed by fusing two standard single-mode optical fibers to form a microbubble and applying a taper on one side of the microbubble to form the asymmetric tapered structure. The strain characteristics of the sensor in the temperature range from room temperature to 425°C are determined.

Research on high sensing performance and multi-band terahertz tunable perfect absorption device.

In this paper, a multi-band terahertz tunable perfect absorption device with high detection performance is proposed. The device has a simple structure, consisting of AlCuFe microstructure, SiO dielectric layer and Au substrate, and has seven resonance peaks (M-M) with high absorption rate, with an average absorption rate of 98.4%.

Design of a Photonic Crystal Fiber Optic Magnetic Field Sensor Based on Surface Plasmon Resonance.

To enhance the sensing performance of fiber-optic magnetic field sensors, we explored the design, optimization, and application prospects of a D-type fiber-optic magnetic field sensor. This D-type PCF-SPR sensor is metal coated on one side (the metal used in this study is gold), which serves as the active metal for SPR and enhances structural stability. Magnetic fluid is applied on the outer side of the gold film for SPR magnetic field sensing.

Electric dipole resonance-driven terahertz broadband absorber with wide-angle and dynamic tunability.

To address the challenges of limited bandwidth and structural complexity in terahertz absorbers, this study proposes a vanadium dioxide (VO)-based broadband terahertz (THz) absorber driven by electric dipole resonance. The device achieves broadband absorption exceeding 90% within 3.55-9.

Infrared band ultra-wideband metamaterial absorption device based on cylindrical multiscale resonator.

Broadband absorption in the mid-infrared and far-infrared regions is of great significance in science and technology. Herein, we developed a mid-far infrared metamaterial absorber, and finite-difference time-domain simulation calculations showed that its average absorption rate in the 6.73-16.

A Highly Sensitive Graphene-Based Terahertz Perfect Absorber Featuring Five Tunable Absorption Peaks.

In this article, we present a high-sensitivity narrow-band perfect graphene absorber that exhibits excellent tunability across multiple bands. The top layer of the absorber unit is composed of graphene material, and the shape is a square graphene layer with a ring structure and a square structure removed from the middle. A SiO dielectric layer is located in the middle, and a layer of gold substrate exists at the bottom.

Multimode Switching Broadband Terahertz Metamaterial Absorbing Micro-Devices Based on Graphene and Vanadium Oxide.

In this paper, we propose a multi-mode switchable ultra-wideband terahertz absorber based on patterned graphene and VO by designing a graphene pattern composed of a large rectangle rotated 45° in the center and four identical small rectangles in the periphery, as well as a VO layer pattern composed of four identical rectangular boxes and small rectangles embedded in the dielectric layer. VO can regulate conductivity via temperature, the Fermi level of graphene depends on the external voltage, and the graphene layer and VO layer produce resonance responses at different frequencies, resulting in high absorption. The proposed absorption microdevices have three modes: Mode 1 (2.

Highly tunable rotationally symmetric multi-band terahertz absorber with enhanced sensing capabilities.

In this study, we propose a novel multi-band absorber structure with exceptional tunability and high performance, aimed at applications in biosensing and medical diagnostics. The absorber consists of a three-layer design, including a gold bottom layer, a silicon dioxide middle layer, and a DSM top layer. The device achieves polarization insensitivity through a rotationally symmetric design, as verified by simulations under varying polarization angles.

Model Design and Study of a U-Channel Photonic Crystal Fib Optic Sensor for Measuring Glucose Concentration in Blood.

This research introduces a biosensor utilizing surface plasmon resonance in a photonic crystal fiber (PCF) configuration. PCF uses fused silica as the base material, with a layer of gold placed over the U-channels in the cross-section of the fiber to create a surface plasmon resonance. There are three different sizes of internal fiber optic air hole diameters, with a larger channel circle below the u-channel for the formation of an energy leakage window.

Visible light compatible infrared stealth capability based on phase change materials.

This study utilizes thermochromic phase change materials VO and GST to design micro-nano structures with temperature-tunable thermal emission characteristics, further controlling their stealth effects in both visible light and infrared backgrounds. Initially, an infrared stealth structure based on GST is proposed. By exploring its crystalline (cGST) and amorphous (aGST) states, the optimal thickness of GST is determined to be 250 nm.

Steerable intrinsic chirality mediated by toroidal dipole bound states in the continuum in an active metasurface.

Chiral metasurfaces supporting bound states in the continuum (BICs) have been extensively researched and gradually applied in biology, sensing, and optical communication due to their strong chiroptical response and ultrahigh-quality () factor. Here, we suggest a feasible pathway to realize steerable chiral metasurfaces with near-unity circular dichroism (CD), high figure of merit (FOM), and sensing sensitivity supported by a toroidal dipole (TD) response, that empower BICs. Through the study of symmetry of metasurfaces, we find that when the up-down and rotational symmetry of the system are broken, one circular () polarization state, carrying a fractional topological charge and separated from the eliminated BIC, can be moved to the Γ point, thereby forming a chiral quasi-BIC mode.

Optimizing energy levels in perovskite solar cells with dual-hole and dual-electron transport layers.

To address the interface carrier recombination and band mismatch associated with the single transport layer design in conventional perovskite solar cells, a dual-electron transport layer (ETL: ZnO/CDS) and a dual-hole transport layer (HTL: Se-Te: CuO/NiO) were proposed. Numerical simulations based on Poisson and carrier continuity equations were employed to systematically investigate the conduction band offset (CBO), valence band offset (VBO), and carrier dynamics. The achievement of optimized energy band alignment and charge transport pathways led to remarkable performance enhancements: the fill factor (FF) increased to 84.

Versatile Tunable Terahertz Absorption Device Based on Bulk Dirac Semimetals and Graphene.

We employed the CST Microwave Studio software 2020 and the FDID algorithm for simulation. We have designed a terahertz broadband absorber based on Dirac semimetals and graphene, achieving continuous broadband absorption with a rate exceeding 80% over the range from 7.6776 to 9.

A terahertz band multifunctional metamaterial transmission-absorption switching device based on vanadium dioxide.

In this paper, a vanadium dioxide (VO)-based terahertz device is proposed to realize the conversion between broadband absorption and broadband transmission functions, including the VO bottom layer, dielectric layer and VO pattern layer in a three-layer structure. With the change of the VO conductivity, the terahertz metamaterial device can switch between broadband absorption and broadband transmission. When the device exhibits broadband transmission, it has a high transmittance of 90% for terahertz waves in the 5.

Thermal radiation analysis of a broadband solar energy-capturing absorber using Ti and GaAs.

This study employed a time-domain finite-difference (FDTD) approach to design an efficient solar energy-capturing absorber consisting of a high melting point metal (Ti) and a semiconductor (GaAs). The structure generated cavity resonance (CR) and surface plasmon resonance (SPR), leading to extremely high absorption across different wavelength bands. The structure exhibited >90% absorption over a wide wavelength range (280-3000 nm).

Photon Reabsorption and Surface Plasmon Modulating Exciton-to-Dopant Energy Transfer Dynamics in Mn:CsPb(BrCl) Quantum Dots.

Exciton-to-dopant energy transfer (ET) dynamics of Mn:CsPbX quantum dots (QDs), which is dominated by diverse physical factors, requires more comprehensive understanding. Here, the concentration-dependent photon reabsorption effect on ET dynamics has been meticulously analyzed in colloidal Mn:CsPb(BrCl) QDs. The results indicate that the photons emitted by the smaller QDs are absorbed by the larger QDs, effectively providing additional excitation light to the latter.

Thermal management broadband-emitting device based on VO applied in the mid-infrared band.

Mid-infrared thermal radiation has attracted attention due to its wide range of applications. Compared to the static process of thermal emission, if thermal radiation can be dynamically controlled, it would be more suitable for practical applications. Herein, we designed a controllable thermal emitter based on phase change materials.

Light Absorption-Enhanced Ultra-Thin Perovskite Solar Cell Based on Cylindrical MAPbI Microstructure.

In order to promote power conversion efficiency and reduce energy loss, we propose a perovskite solar cell based on cylindrical MAPbI3 microstructure composed of a MAPbI perovskite layer and a hole transport layer (HTL) composed of PEDOT:PSS. According to the charge transport theory, which effectually increases the contact area of the HTL, promoting the electronic transmission capability, the local field enhancement and scattering effects of the surface plasmon polaritons help to couple the incident light to the solar cell, which can increase the absorption of light in the active layer of the solar cell and improve its light absorption efficiency (LAE). based on simulation results, a cylindrical microstructure of the perovskite layer increases the contact area of the hole transport layer, which could improve light absorption, quantum efficiency (QE), short-circuit current density (J), and electric power compared with the perovskite layer of other structures.

A perfect ultra-wideband solar absorber with a multilayer stacked structure of Ti-SiO-GaAs: structure and outstanding characteristics.

In this paper, we introduce an entirely new solar absorber design-a multi-layer periodic stacked structure. Through coupling effects, this design has perfect ultra-wideband absorption characteristics. The absorber structure is composed of four absorption units with varying cycle lengths, which are cyclically stacked on the surface of the refractory metal Cr.

A Polarization-Insensitive and Highly Sensitive THz Metamaterial Multi-Band Perfect Absorber.

In this article, we present a terahertz (THz) metamaterial absorber that blends two types of coordinated materials: Dirac semimetals and vanadium dioxide. Compared to other absorbers on the market, which are currently non-adjustable or have a single adjustment method, our absorber is superior because it has two coordinated modes with maximum adjustment ranges of 80.7% and 0.