Metasurface-based near perfect absorbers exhibit a wide range of potential applications in the fields of solar energy harvesting, thermal images and sensors due to their unique absorption regulation function. However, absorption characteristics of devices are locked by the device structure, leading to the limitation in real-time dynamic applications. In this work, we integrate the phase change material VO thin film into the metal-insulator-metal structured metasurface based absorber, and design a fully visible band switchable dynamically tunable absorber (DTA). By controlling the phase transition of VO, the DTA can realize a novel switch function in the full band of visible light (400 ∼ 780 nm), with absorption contrast ranges from 42% to 60%. Furthermore, via accurate structural parameter control, the vivid cyan, magenta, and yellow pixels based on the VO DTA are designed and proposed in the real-time optical anti-counterfeiting, exhibiting outstanding characteristics of anti-glare interference and real-time encryption ability. The absorption spectrum and local electric field are simulated and analyzed to study the internal operation mechanism of DTA. The dynamic absorption adjustable function is attributed to the synergistic effect of insulator-metal transition of VO and Fabry-Pérot resonance of absorber.
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http://dx.doi.org/10.1364/OE.412991 | DOI Listing |
Sci Rep
December 2024
Department of Electronics, Carleton University, Ottawa, ON, K1S 5B6, Canada.
In this paper, we propose a novel structure of anisotropic graphene-based hyperbolic metamaterial (AGHMM) sandwiched as a defect between two one-dimensional photonic crystals (PCs) in the terahertz (THz) region. The proposed structure is numerically simulated and analyzed using the transfer matrix method, effective medium theory and three-dimensional finite-difference time-domain. The defect layer of AGHMM consists of graphene sheets separated by subwavelength dielectric spacers.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Mechanical and Aerospace Engineering, University at Buffalo (State University of New York), Buffalo, NY 14260-4400.
Decades after being replaced with digital platforms, analogue computing has experienced a surging interest following developments in metamaterials and intricate fabrication techniques. Specifically, wave-based analogue computers which impart spatial transformations on an incident wavefront, commensurate with a desired mathematical operation, have gained traction owing to their ability to directly encode the input in its unprocessed form, bypassing analogue-to-digital conversion. While promising, these systems are inherently limited to single-task configurations.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
College of Architecture & Civil Engineering, Shangqiu Normal University, Shangqiu, 476000, China.
The rational design of microwave absorption (MA) material featuring light weight, wide absorption bandwidth, and infrared stealth property is crucial for military stealth and health protection but remains challenging. Herein, an innovative N-doped carbon nanocage-in-microcage structure with tunable carbon-coated Ni (NC/Ni(HS)) is reported via a reliable Ni-catalyzed and Ni-templated method. The hierarchically hollow structure of nanocage-in-microcage composites can optimize the impedance matching and respond to multiple reflections and scattering of incident microwaves and infrared waves.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Xi'an Key Laboratory of Extreme Environment and Protection Technology, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Tunable perfect acoustic absorption at subwavelength thickness has been a prominent topic in scientific research and engineering applications. Although metamaterials such as labyrinthine metasurfaces and coiling-up-space metamaterials can achieve subwavelength low-frequency acoustic absorption, efficiently realizing tunable absorption under uniform and limited size conditions remains challenging. In this paper, we introduce a folded slit to enhance the micro-slit acoustic absorber, effectively improving its low-frequency acoustic absorption performance and successfully achieving a perfect acoustic absorption coefficient of 0.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Guangdong Provincial Key Laboratory of Optoelectronic Information Processing Chips and Systems, School of Microelectronics Science and Technology, Sun Yat-sen University, Zhuhai 519082, China.
The strong coupling between infrared photonic resonances and vibrational transitions of organic molecules is called vibrational strong coupling (VSC), which presents attractive prospects for modifying molecular chemical characteristics and behaviors. Currently, VSC studies suffer from limited bandwidth or enormous mode volumes. In addition, in certain instances, the absorption spectrum of VSC is weaker, thus impeding the effective monitoring of the VSC effect.
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