In a recent paper, Zhao et al. [Opt. Express 19(12), 11605 (2011)], proposed the use of differential evolution technique to optimize figure of merit of a negative index metamaterial (NIM) for the visible spectrum. In this comment, we argue that certain ambiguities associated with the effective parameter retrieval should be also addressed in the paper for the accurate implementation of the technique for NIMs. Furthermore, the figure of merit reported in the paper is unrealistically large.
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http://dx.doi.org/10.1364/OE.22.003773 | DOI Listing |
Nanophotonics
January 2025
MOE Key Laboratory of Advanced Micro-Structured Materials, School of Physics Science and Engineering Tongji University, Shanghai 200092, China.
The formed optical cavity mode intensively relies on the size and geometry of optical cavity. When the defect or impurity exists inside the cavity, the formed cavity mode will be destroyed. Here, we propose a metacavity consisting of arrays of linear-crossing metamaterials (LCMMs) with abnormal dispersion, where each LCMM offers both the directional propagation channel for all incident angles and the negative refraction across its neighboring LCMMs.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Institute of Fundamental Technological Research, Polish Academy of Sciences, ul. Pawińskiego 5B, 02-106 Warsaw, Poland.
In this paper, we demonstrate that torsional surface elastic waves can propagate along the curved surface of a metamaterial elastic rod (cylinder) embedded in a conventional elastic medium. The crucial parameter of the metamaterial rod is its elastic compliance s44(1)ω, which varies as a function of frequency ω analogously to the dielectric function εω in Drude's model of metals. As a consequence, the elastic compliance s44(1)ω can take negative values s44(1)ω<0 as a function of frequency ω.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Electronic Engineering, Tsinghua University, Beijing 100084, China.
Fano resonance is achieved by tuning two coupled oscillators and has exceptional potential for modulating light dispersion. Here, distinct from the classical Fano resonances achieved through photonics methodologies, we introduce the Fano resonance in epsilon-near-zero (ENZ) media with novel electromagnetic properties. By adjusting the background permeability of the ENZ host, the transmission spectrum exhibits various dispersive line shapes and covers the full range of Fano parameter q morphologies, from negative to positive infinity.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore.
Mechanical metamaterials exhibit several unusual mechanical properties, such as a negative Poisson's ratio, which impart additional capabilities to materials. Recently, hydrogels have emerged as exceptional candidates for fabricating mechanical metamaterials that offer enhanced functionality and expanded applications due to their unique responsive characteristics. However, the adaptability of these metamaterials remains constrained and underutilized, as they lack integration of the hydrogels' soft and responsive characteristics with the metamaterial design.
View Article and Find Full Text PDFMaterials (Basel)
November 2024
School of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Roll-bonding has rarely been applied to prepare rods for negative thermal expansion metamaterials (NTEMs). Parameters for quantitatively assessing the isotropy and cyclic thermal stability of the thermal expansion coefficient α of NTEMs are lacking. Here, the Ti-to-Al thickness ratio in bimetallic rods for "cross-shaped" node bending-dominated NTEMs was optimized using a general model proposed in the literature.
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