Metamaterials and Phononic Crystals

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Inorganic Crystalline Materials".

Deadline for manuscript submissions: closed (20 September 2024) | Viewed by 7635

Special Issue Editors

Department of Mechanical Engineering, University of Vermont, Burlington, VT 05405, USA
Interests: nanocrystals; metamaterials

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Guest Editor
Department of Mechanical Engineering, University of Louisville, Louisville, KY 40292, USA
Interests: phononic metamaterials; architected metamaterials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Phononic crystals (PnCs) and acoustic metamaterials (AMMs) are artificially architected materials endowed with the capabilities of wave manipulation, such as mechanical filtering and wave directionality, waveguiding, acoustic cloaking, and energy trapping. As unit cell characteristics determine the bulk wave propagation, the symmetry and topology of a unit cell can yield many more exotic features, such as the manifestation of bulk characteristics on edges or corners, also known as the bulk edge correspondence.

In this Special Issue of Crystals, we aim to solicit original research articles, letters, communications, and literature reviews on the development of phononic crystals and metamaterials. Potential topics include, but are not limited to:

  • The fundamental principles of phononic crystals, metamaterials, and metasurfaces.
  • The design, manufacturing, and characterization of phononic crystals, metamaterials, and metasurfaces.
  • The synthesis, advanced manufacturing, and characterization of phononic crystals and metamaterials at the nano- and microscales.
  • The atomistic modeling of nanoscale phononic crystals and metamaterials.
  • Topological phononic crystals and metamaterials.
  • Tunable metamaterials, phononic crystals, and metasurfaces.
  • Temporally modulated phononic media.
  • Nonlinear phononics.
  • Thermal phononics.
  • Numerical methods for complex phononic systems.
  • Applications of phononic crystals, metamaterials, and metasurfaces.

Dr. Jihong Ma
Dr. Yanyu Chen
Guest Editors

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Keywords

  • phononic crystals
  • metamaterials
  • metasurfaces
  • vibration
  • wave propagation
  • phonons
  • theories
  • simulations
  • experimental characterization
  • synthesis
  • manufacturing
  • fabrication
  • topological phonons
  • nonlinearity
  • numerical methods
  • applications
  • thermal phonons

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Published Papers (5 papers)

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Research

16 pages, 2280 KiB  
Article
Experimental Validation for Mechanically Tunable Defect Bands of a Reconfigurable Phononic Crystal with Permanent Magnets
by Jeonggyu Yang and Soo-Ho Jo
Crystals 2024, 14(8), 701; https://doi.org/10.3390/cryst14080701 - 1 Aug 2024
Viewed by 780
Abstract
Phononic crystals (PnCs) have garnered significant attention due to their unique ability to control elastic waves in unconventional ways. One area of research focuses on utilizing defects within PnCs. Defects create new pass bands within band gaps, leading to concentrated wave energy within [...] Read more.
Phononic crystals (PnCs) have garnered significant attention due to their unique ability to control elastic waves in unconventional ways. One area of research focuses on utilizing defects within PnCs. Defects create new pass bands within band gaps, leading to concentrated wave energy within the defects. However, defect-mode-enabled wave localization is effective only at specific frequencies, limiting its usefulness when the frequencies of incident waves vary. Existing methods to mechanically tune defect bands involve changing the geometries of unit cells or defects or attaching elastic foundations, which necessitates the detachment and reattachment of certain structures depending on the engineering situation. Considering these challenges, this study introduces a novel approach that utilizes the reconfigurable PnC design, incorporating permanent magnets and ferromagnetic materials. The case study involves a one-dimensional PnC consisting of a long metal beam with rectangular block-shaped permanent magnets periodically arranged and attached to the beam by magnetic forces. A defect is created by shifting a subset of these block-shaped permanent magnets in parallel. The extent of this parallel movement alters the vibrating characteristics of the defect, facilitating the mechanical control of the defect bands in the defective PnC. The effectiveness of this approach is experimentally validated. Full article
(This article belongs to the Special Issue Metamaterials and Phononic Crystals)
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15 pages, 7354 KiB  
Article
In-Gap Edge and Domain-Wall States in Largely Perturbed Phononic Su–Schrieffer–Heeger Lattices
by Amir Rajabpoor Alisepahi and Jihong Ma
Crystals 2024, 14(1), 102; https://doi.org/10.3390/cryst14010102 - 22 Jan 2024
Cited by 1 | Viewed by 1563
Abstract
Topological states of matter have attracted significant attention due to their intrinsic wave-guiding and localization capabilities robust against disorders and defects in electronic, photonic, and phononic systems. Despite the above topological features that phononic crystals share with their electronic and photonic counterparts, finite-frequency [...] Read more.
Topological states of matter have attracted significant attention due to their intrinsic wave-guiding and localization capabilities robust against disorders and defects in electronic, photonic, and phononic systems. Despite the above topological features that phononic crystals share with their electronic and photonic counterparts, finite-frequency topological states in phononic crystals may not always survive. In this work, we discuss the survivability of topological states in Su–Schrieffer–Heeger models with both local and non-local interactions and larger symmetry perturbation. Although such a discussion is still about ideal mass-spring models, the insights from this study set the expectations for continuum phononic crystals, which can further instruct the application of phononic crystals for practical purposes. Full article
(This article belongs to the Special Issue Metamaterials and Phononic Crystals)
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14 pages, 2963 KiB  
Article
Photonic Crystal Waveguides Composed of Hyperbolic Metamaterials for High-FOM Nano-Sensing
by Yaoxian Zheng, Fahim Khan, Barkathulla Asrafali and Qiong Wang
Crystals 2023, 13(9), 1389; https://doi.org/10.3390/cryst13091389 - 18 Sep 2023
Cited by 1 | Viewed by 1361
Abstract
This study introduces an innovative integration of hyperbolic metamaterials (HMMs) and photonic crystals (PtCs), each possessing unique dispersion properties that effectively manipulate the propagation of light. We present a PtC waveguide consisting of arrays of HMM nanorods, denoted as HMM PtCs. This waveguide [...] Read more.
This study introduces an innovative integration of hyperbolic metamaterials (HMMs) and photonic crystals (PtCs), each possessing unique dispersion properties that effectively manipulate the propagation of light. We present a PtC waveguide consisting of arrays of HMM nanorods, denoted as HMM PtCs. This waveguide configuration enables the realization of a high figure of merit (FOM) nano-sensor. HMMs and PtCs share the same underlying physics. HMMs can generate surface plasmonics, while PtCs offer a bandgap for the waveguide. This configuration presents a novel sensing solution that directly couples surface plasmonics and waveguide modes. By modifying the refractive indices of the surrounding materials, the PtC waveguide exhibits alterations in absorption and transmission, allowing for the detection of temperature, pressure, and material variations. The refractive indices of the surrounding materials can be adjusted based on the sensor’s intended application. For instance, when the sensor is utilized for temperature sensing, thermal infrared materials can serve as the surrounding medium. As the temperature rises, the refractive index of the surrounding material changes accordingly, impacting the waveguide modes and thereby altering absorption and transmission. We utilized the finite element method to conduct numerical simulations in order to assess the absorption and transmission characteristics of the proposed system. Given that this approach involves a full electromagnetic calculation based on Maxwell’s equations, it closely approximates real-world scenarios. The employed numerical method demonstrates the remarkable performance of this proposed system, achieving a sensitivity of 324.16 nm/RIU (refractive index unit) and an impressive FOM of 469.58 RIU−1. These results signify a substantial improvement over surface plasmonic sensors, which typically exhibit limited FOMs. The direct coupling between surface plasmonics and waveguide modes provides a distinct advantage, allowing the proposed sensor to deliver a superior performance. As a consequence, the HMM PtC waveguide sensor emerges as an exceptionally appealing option for photonic sensing applications. The complexity of the proposed system presents a fabrication challenge. Nevertheless, as fabrication technology continues to advance, we anticipate that this issue can be effectively resolved. The proposed HMM PtC waveguide holds vast potential across diverse fields, including biology, medicine, and clinics, representing an exciting advancement for both industry and scientific research. Full article
(This article belongs to the Special Issue Metamaterials and Phononic Crystals)
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14 pages, 4072 KiB  
Article
A Nonlinear Gradient-Coiling Metamaterial for Enhanced Acoustic Signal Sensing
by Guodong Hao, Xinsa Zhao and Jianning Han
Crystals 2023, 13(8), 1291; https://doi.org/10.3390/cryst13081291 - 21 Aug 2023
Cited by 4 | Viewed by 1576
Abstract
Acoustic sensing systems play a critical role in identifying and determining weak sound sources in various fields. In many fault warning and environmental monitoring processes, sound-based sensing techniques are highly valued for their information-rich and non-contact advantages. However, noise signals from the environment [...] Read more.
Acoustic sensing systems play a critical role in identifying and determining weak sound sources in various fields. In many fault warning and environmental monitoring processes, sound-based sensing techniques are highly valued for their information-rich and non-contact advantages. However, noise signals from the environment reduce the signal-to-noise ratio (SNR) of conventional acoustic sensing systems. Therefore, we proposed novel nonlinear gradient-coiling metamaterials (NGCMs) to sense weak effective signals from complex environments using the strong wave compression effect coupled with the equivalent medium mechanism. Theoretical derivations and finite element simulations of NGCMs were executed to verify the properties of the designed metamaterials. Compared with nonlinear gradient acoustic metamaterials (Nonlinear-GAMs) without coiling structures, NGCMs exhibit far superior performance in terms of acoustic enhancement, and the structures capture lower frequencies and possess a wider angle acoustic response. Additionally, experiments were constructed and conducted using set Gaussian pulse and harmonic acoustic signals as emission sources to simulate real application scenarios. It is unanimously shown that NGCMs have unique advantages and broad application prospects in the application of weak acoustic signal sensing, enhancement and localization. Full article
(This article belongs to the Special Issue Metamaterials and Phononic Crystals)
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14 pages, 3194 KiB  
Article
Phononic Crystal Coupled Mie Structure for Acoustic Amplification
by Jianning Han, Guodong Hao, Wenying Yang and Xinsa Zhao
Crystals 2023, 13(8), 1196; https://doi.org/10.3390/cryst13081196 - 1 Aug 2023
Cited by 3 | Viewed by 1756
Abstract
In the field of industrial structure detection, acoustic signals have been pivotal. A cost-effective and highly sensitive acoustic monitoring system that can enhance weak acoustic signals has always been an interesting topic in many research fields. However, environmental noise signals have consistently hindered [...] Read more.
In the field of industrial structure detection, acoustic signals have been pivotal. A cost-effective and highly sensitive acoustic monitoring system that can enhance weak acoustic signals has always been an interesting topic in many research fields. However, environmental noise signals have consistently hindered the improvement of the signal-to-noise ratio (SNR) of traditional acoustic systems. In this work, we propose a structure (PC-Mie) that couples phononic crystal (PC) point defects and Mie resonance structures (Mies) to enhance weak effective signals from complex environments. Numerical simulations have confirmed that the PC-Mie exhibits superior sound pressure enhancement performance compared to each individual PC point defect and Mies. Moreover, the capability to amplify the sound pressure amplitude is related to the angle and position of the Mies at the center position. Simultaneously, the PC-Mie has a narrower bandwidth, giving the structure stronger frequency selectivity. Finally, the experiment proves that PC-Mie can function as an enhanced acoustic device or sensor to detect harmonic signals, verifying the validity of the PC-Mie structure for acoustically enhanced perception. Both numerical and experimental studies demonstrate that the PC-Mie can effectively enhance the energy of specific sound frequencies in complex air environments, making it suitable for collecting high-sensitivity acoustic signals. This research has significant implications for the development of weak acoustic signal detection technology and the application of self-powered sensors. Full article
(This article belongs to the Special Issue Metamaterials and Phononic Crystals)
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