A tunable dual broadband switchable terahertz absorber based on vanadium dioxide and graphene is proposed. The tunability of graphene and the phase transition properties of vanadium dioxide are used to switch broadband absorption between low-frequency and high-frequency, as well as the absorption rate tuning function. The simulation results indicate that when vanadium dioxide is in the insulating phase and the graphene Fermi energy is 0.7 eV, the absorber achieves low-frequency broadband absorption within the range of 2.6-4.2 THz with an absorptance greater than 90%; when vanadium dioxide is in the metallic phase and the graphene Fermi energy is 0 eV, the absorber achieves high-frequency broadband absorption within the range of 4.9-10 THz with an absorptance greater than 90%. Furthermore, the absorptance can be tuned by adjusting the conductivity of vanadium dioxide or the Fermi energy of graphene. Due to the central symmetry of the proposed structure, the absorber is completely insensitive to polarization. For TE and TM polarized waves, both low and high-frequency broadband absorption are maintained over a range of incident angles from 0° to 50°. The simple structure, tunable absorption rate, insensitivity to polarization angle and incident angle properties are advantages of our proposed absorber. It has broad application prospects in adjustable filters and electromagnetic shielding.
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http://dx.doi.org/10.1039/d3cp01312j | DOI Listing |
ACS Appl Mater Interfaces
December 2024
Anhui Province Key Laboratory for Control and Applications of Optoelectronic Information Materials, School of Physics and Electronic Information, Anhui Normal University, 189 Jiuhua South Road, Wuhu 241003, China.
Integrating metal nanoparticles with vanadium dioxide (VO) is an effective means to realize active plasmonic regulation which has great application potential in optical devices that respond in real-time to external stimuli. However, the high temperature necessary for VO growth severely reshapes the metal nanoparticles, causing reduced refractive index (RI) sensitivity and degraded modulation performance. Herein, we construct a large-area dynamically tunable plasmonic system composed of a VO-covered array of hexagonal gold nanoplates (AuNPLs).
View Article and Find Full Text PDFNanophotonics
November 2024
National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China.
Non-local metasurface supporting geometric phases at bound states in the continuum (BIC) simultaneously enables sharp spectral resonances and spatial wavefront shaping, thus providing a diversified optical platform for multifunctional devices. However, a static nonlocal metasurface cannot manipulate multiple degrees of freedom (DOFs), making it difficult to achieve multifunctional integration and be applied in different scenarios. Here, we presented and demonstrated phase-change non-local metasurfaces that can realize dynamic manipulation of multiple DOFs including resonant frequency, values, band, and spatial wavefront.
View Article and Find Full Text PDFAdv Mater
December 2024
School of Optics and Photonics, Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing, 100081, China.
The Pancharatnam-Berry (PB) phase has revolutionized the design of metasurfaces, offering a straightforward and robust method for controlling wavefronts of electromagnetic waves. However, traditional metasurfaces have fixed PB phases determined by the orientation of their individual elements. In this study, an innovative structural design and integration scheme is proposed that utilizes vanadium dioxide, a phase-change material, to achieve thermally controlled dynamic PB phase control within the metasurface.
View Article and Find Full Text PDFExceptional points (EPs) have been the subject of wide concern because of their unique physical properties and have produced many related applications. However, up to now, most non-Hermitian metasurfaces related to EPs focus on realizing a single function. It remains a challenge to integrate multiple functions into a single non-Hermitian metasurface while making it dynamically adjustable.
View Article and Find Full Text PDFNanophotonics
March 2024
Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR 999077, China.
Radiative cooling in smart windows using VO - a dynamic thermal management material, is of potential interest for enhancing energy savings in buildings due to its both solar and emittance tuneability in response to changing temperatures. However, studies related to the effects of VO thin film microstructure in a multilayer system on emissivity regulation are currently lacking. The present study addresses the thermochromic and emissivity performance of VO/ZnSe/ITO/Glass Fabry-Perot (F-P) cavity thin film system, by manipulating the porosity in VO thin film.
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