Recent Advances in Phononic Crystals and Acoustic Metamaterials (Volume II)

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

Deadline for manuscript submissions: closed (30 April 2023) | Viewed by 5746

Special Issue Editors


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Guest Editor
Department of Mechanical Engineering, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan
Interests: phononic crystals; acoustic metamaterial; acoustofluidic manipulation; guided waves in piezoelectric materials
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Guest Editor
Department of Mechanical Engineering, Chang Gung University, Taoyuan City 333, Taiwan
Interests: phononic crystals; acoustic metamaterial; nondestructive testing; wave signal analysis by machine learning and AI
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Phononic crystals and acoustic metamaterials are artificial materials that exhibit extraordinary physical phenomena, functions, and properties in acoustics. Phononic crystals are generally periodic elastic composites or structures designed with local defects for controlling acoustic wave propagation. Acoustic metamaterials are presented as relatively architectured materials composed of periodic or random distributions of subwavelength resonating units for generating unusual acoustical/physical parameters. Both derive their novel characteristics from the interaction between acoustic waves and designed materials. They have drawn significant attention from both the physics and engineering communities as they lie at the crossroads of vibration and acoustics engineering and condensed matter. This field has also been greatly advanced by scientists and researchers during the past decades. The territory involves disciplines from phonon physics in micro- and nanoscale systems, physical acoustics, acoustic-wave sensors and devices, sound-and-noise control of seismic waves, and vibration, which cover broad applications of the acoustic waves in a variety of frequency ranges. Phononic crystals and acoustic metamaterials have been decidedly demonstrating their potential and promising applications in the acoustic-wave spectrum both for now and the future.

In this Special Issue, we would like to invite all contributions related to phononic crystals and acoustic metamaterials. Theoretical, numerical, and experimental studies and investigations on these artificial materials are welcome. This Special Issue aims to publish novel research results but also to provide a comprehensive understanding of the physics, mechanisms, materials, analyzing methods, applications, and recent development of phononic crystals and acoustic metamaterials. In light of recent advances, research articles, short communications, and review articles related but not limited to the following topics are encouraged for submission to this Special Issue.

  • thermal phononic crystals
  • topological phononic crystals
  • phononic/phoxonic sensors
  • phoxonic crystals and acousto-optic coupling
  • functional metamaterials
  • micro and nanoscale phononic crystals
  • acoustic metasurfaces
  • sonic crystals/metamaterials
  • underwater metamaterials (solid–fluid interaction)
  • seismic metamaterials
  • applications and devices with phononic crystals and acoustic metamaterials

Prof. Dr. Jin-Chen Hsu
Dr. Jia-Hong Sun
Guest Editors

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Keywords

  • elastic wave
  • acoustic wave
  • phononic crystal
  • metamaterial
  • metasurface
  • phonon
  • ultrasound
  • periodic material
  • local resonance
  • vibration
  • band gap

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Related Special Issue

Published Papers (3 papers)

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Research

19 pages, 9053 KiB  
Article
Reflections of High-Frequency Pulsed Ultrasound by Underwater Acoustic Metasurfaces Composed of Subwavelength Phase-Gradient Slits
by Jin-Chen Hsu, Herwandi Alwi, Chun-Hao Wei, Kai-Li Liao and Che-Ting Huang
Crystals 2023, 13(5), 846; https://doi.org/10.3390/cryst13050846 - 20 May 2023
Cited by 4 | Viewed by 1758
Abstract
We numerically and experimentally investigated the behavior of high-frequency underwater ultrasounds reflected by gradient acoustic metasurfaces. Metasurfaces were fabricated with a periodic array of gradient slits along the surface of a steel specimen. The finite element method was adopted for the acoustics–structure interaction [...] Read more.
We numerically and experimentally investigated the behavior of high-frequency underwater ultrasounds reflected by gradient acoustic metasurfaces. Metasurfaces were fabricated with a periodic array of gradient slits along the surface of a steel specimen. The finite element method was adopted for the acoustics–structure interaction problem to design the metasurfaces and simulate the reflected fields of the incident ultrasound. Our metasurfaces yielded anomalous reflection, specular reflection, apparent negative reflection, and radiation of surface-bounded modes for ultrasonic waves impinging on the metasurfaces at different incident angles. The occurrence of these reflection behaviors could be explained by the generalized Snell’s law for a gradient metasurface with periodic supercells. We showed that at some incident angles, strong anomalous reflection could be generated, which could lead to strong retroreflection at specific incident angles. Furthermore, we characterized the time evolution of the reflections using pulsed ultrasound. The simulated transient process revealed the formation of propagating reflected ultrasound fields. The experimentally measured reflected ultrasound signals verified the distinct reflection behaviors of the metasurfaces; strong anomalous reflection steering the ultrasound pulse and causing retroreflection was observed. This study paves the way for designing underwater acoustic metasurfaces for ultrasound imaging and caustic engineering applications using pulsed ultrasound in the high-frequency regime. Full article
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11 pages, 2163 KiB  
Article
High-Q Slow Sound Mode in a Phononic Fishbone Nanobeam Using an Acoustic Potential Well Cavity
by Ying-Pin Tsai, Bor-Shyh Lin and Fu-Li Hsiao
Crystals 2023, 13(1), 95; https://doi.org/10.3390/cryst13010095 - 4 Jan 2023
Cited by 1 | Viewed by 1562
Abstract
Phononic crystals and phononic metamaterials are popular structures for manipulating acoustic waves with artificially arranged units that have different elastic constants. These structures are also used in acousto-optic coupling and optomechanical structures. In such research, a 1-D nanobeam containing a cavity region sandwiched [...] Read more.
Phononic crystals and phononic metamaterials are popular structures for manipulating acoustic waves with artificially arranged units that have different elastic constants. These structures are also used in acousto-optic coupling and optomechanical structures. In such research, a 1-D nanobeam containing a cavity region sandwiched by two mirror regions is one of the most common designs. However, searching bandgaps for suitable operation modes and the need for the mirror region are limitations in the device design. Therefore, we introduce the slow sound mode as the operating acoustic mode and use an acoustic potential well to further trap the phonons in the cavity. Three types of structures are introduced to investigate the effect of the potential well. The products of the mode frequencies and the quality factors of the modes are used to demonstrate the performance of the structures. The displacement field and the strain field show the concentrated slow sound modes of the potential wells and produce high quality factors. Full article
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19 pages, 2943 KiB  
Article
Tunable Topological Acoustic Tamm States in Comblike Structures Based on Band Inversion around Flat Bands
by Soufyane Khattou, Yamina Rezzouk, Madiha Amrani, Mohamed El Ghafiani, El Houssaine El Boudouti, Abdelkrim Talbi and Bahram Djafari-Rouhani
Crystals 2022, 12(12), 1685; https://doi.org/10.3390/cryst12121685 - 22 Nov 2022
Cited by 3 | Viewed by 1718
Abstract
We investigate the existence of acoustic Tamm states at the interface between two one-dimensional (1D) comblike phononic crystals (PnCs) based on slender tubes and discuss their topological or trivial character. The PnCs consist of stubs grafted periodically along a waveguide and the two [...] Read more.
We investigate the existence of acoustic Tamm states at the interface between two one-dimensional (1D) comblike phononic crystals (PnCs) based on slender tubes and discuss their topological or trivial character. The PnCs consist of stubs grafted periodically along a waveguide and the two crystals differ by their geometrical parameters (period and length of the stubs). We use several approaches to discuss the existence of Tamm states and their topology when connecting two half-crystals. First, we derive a necessary and sufficient condition on the existence of interface states based on the analysis of the bulk band structure and the symmetry of the band edge states. This approach is equivalent to an analysis of the Zak phases of the bulk bands in the two crystals. Indeed, a topological interface state should necessarily exist in any common bandgap of the two PnCs for which the lower (upper) band edges have opposite symmetries. A novelty of our structure consists in the fact that the symmetry inversion results from a band closure (flat band) rather than from a gap closure, in contrast to previous works. Then, such interface states are revealed through different physical quantities, namely: (i) the local density of states (LDOS), which exhibits a high localization around the interface; (ii) sharp peaks in the transmission spectra in the common bandgap when two finite crystals are connected together; (iii) the phases of the reflection coefficients at the boundary of each PnC with a waveguide, which have a direct relationship with the Zak phases. In addition, we show that the interface states can transform to bound states in the continuum (BICs). These BICs are induced by the cavity separating both PnCs and they remain robust to any geometrical disorder induced by the stubs and segments around this cavity. Finally, we show the impossibility of interface states between two connected PnCs with different stub lengths and similar periods. The sensitivity of these states to interface perturbations can find many practical applications in PnC sensors. Full article
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