We report on a continuous electromagnetic metal planar metamaterial, which resembles a "fish scale" structure. Apart from the one isolated wavelength, it is highly transparent to electromagnetic radiation throughout a broad spectral range and becomes completely "invisible" at some frequency inflicting no transmission losses and phase delay. When the structure is superimposed on a metallic mirror it becomes a good broadband reflector everywhere apart from one wavelength where the reflectivity is small. At this wavelength the reflected wave shows no phase change with respect to the incident wave, thus resembling a reflection from a hypothetical zero refractive index material, or "magnetic wall." We also discovered that the structure acts as a local field concentrator and a resonant "amplifier" of losses in the underlying dielectric.
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http://dx.doi.org/10.1103/PhysRevE.72.056613 | DOI Listing |
Luminescence
January 2025
Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
Aiming at net-zero emissions, most international and national policies focus on sustainable development goals. Hence, there is an immediate need for replacing carbon-intensive materials with biomaterials. In this respect, this article presents a road-map for moving from polymeric to sustainable waveguides in optical devices.
View Article and Find Full Text PDFSci Rep
January 2025
School of Electrical Engineering, University of Tehran, Tehran, 14179-35840, Iran.
This paper introduces an analytical method for studying power transmission through an infinite array of helical-shaped metal particles in a lossy dielectric medium. While the assessment of composite slabs' transmitted power has been extensively researched in the electromagnetic interference (EMI) shielding field, many studies lack an adequate problem description. The primary inadequacy of these studies is the need for an analytical framework.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, The Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Division of Life Science, State Key Laboratory of Molecular Neuroscience, and Department of Chemical & Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China.
The two contradictory entities in nature often follow the principle of unity of opposites, leading to optimal overall performance. Particularly, aggregation-induced emission luminogens (AIEgens) with donor-acceptor (D-A) structures exhibit tunable optical properties and versatile functionalities, offering significant potential to revolutionize cancer treatment. However, trapped by low molar absorptivity (ε) owing to the distorted configurations, the ceilings of their photon-harvesting capability and the corresponding phototheranostic performance still fall short.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
Tianmushan Laboratory, Yuhang District, Hangzhou 311115, China.
The continuous expansion of wireless communication application scenarios demands the active tuning of electromagnetic (EM) metamaterials, which is essential for their flexible adaptation to complex EM environments. However, EM reconfigurable systems based on intricate designs and smart materials often exhibit limited flexibility and incur high manufacturing costs. Inspired by mechanical metastructures capable of switching between multistable configurations under repeated deformation, we propose a planar kirigami frequency selective surface (FSS) that enables mechanical control of its resonant frequency.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
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