TY - JOUR
T1 - Perspective: Acoustic metamaterials in transition
T2 - Acoustic metamaterials in transition
AU - Wu, Ying
AU - Yang, Min
AU - Sheng, Ping
N1 - KAUST Repository Item: Exported on 2020-04-23
Acknowledged KAUST grant number(s): BAS/1/1626-01-01
Acknowledgements: Y.W. wishes to acknowledge funding support from King Abdullah University of Science and Technology BAS/1/1626-01-01. P.S. wishes to acknowledge funding support from Hong Kong Government Grant Nos. AoE/P-02/12 and ITF UIM292.
PY - 2017/12/15
Y1 - 2017/12/15
N2 - Acoustic metamaterials derive their novel characteristics from the interaction between acoustic waves with designed structures. Since its inception seventeen years ago, the field has been driven by fundamental geometric and physical principles that guide the structure design rules as well as provide the basis for wave functionalities. Recent examples include resonance-based acoustic metasurfaces that offer flexible control of acoustic wave propagation such as focusing and re-direction; parity-time (PT)-symmetric acoustics that utilizes the general concept of pairing loss and gain to achieve perfect absorption at a single frequency; and topological phononics that can provide one-way edge state propagation. However, such novel functionalities are not without constraints. Metasurface elements rely on resonances to enhance their coupling to the incident wave; hence, its functionality is limited to a narrow frequency band. Topological phononics is the result of the special lattice symmetry that must be fixed at the fabrication stage. Overcoming such constraints naturally forms the basis for further developments. We identify two emergent directions: Integration of acoustic metamaterial elements for achieving broadband characteristics as well as acoustic wave manipulation tasks more complex than the single demonstrative functionality; and active acoustic metamaterials that can adapt to environment as well as to go beyond the constraints on the passive acoustic metamaterials. Examples of a successful recent integration of multi-resonators in achieving broadband sound absorption can be found in optimal sound-absorbing structures, which utilize causality constraint as a design tool in realizing the target-set absorption spectrum with a minimal sample thickness. Active acoustic metamaterials have also demonstrated the capability to tune bandgaps as well as to alter property of resonances in real time through stiffening of the spring constants, in addition to the PT symmetric acoustics that can achieve unprecedented functionalities. These emergent directions portend the transitioning of the field from the stage of novelty demonstrations to imminent applications of some acoustic metamaterials to select real-world problems, supported by an active research endeavor that continues to push the boundary of possibilities.
AB - Acoustic metamaterials derive their novel characteristics from the interaction between acoustic waves with designed structures. Since its inception seventeen years ago, the field has been driven by fundamental geometric and physical principles that guide the structure design rules as well as provide the basis for wave functionalities. Recent examples include resonance-based acoustic metasurfaces that offer flexible control of acoustic wave propagation such as focusing and re-direction; parity-time (PT)-symmetric acoustics that utilizes the general concept of pairing loss and gain to achieve perfect absorption at a single frequency; and topological phononics that can provide one-way edge state propagation. However, such novel functionalities are not without constraints. Metasurface elements rely on resonances to enhance their coupling to the incident wave; hence, its functionality is limited to a narrow frequency band. Topological phononics is the result of the special lattice symmetry that must be fixed at the fabrication stage. Overcoming such constraints naturally forms the basis for further developments. We identify two emergent directions: Integration of acoustic metamaterial elements for achieving broadband characteristics as well as acoustic wave manipulation tasks more complex than the single demonstrative functionality; and active acoustic metamaterials that can adapt to environment as well as to go beyond the constraints on the passive acoustic metamaterials. Examples of a successful recent integration of multi-resonators in achieving broadband sound absorption can be found in optimal sound-absorbing structures, which utilize causality constraint as a design tool in realizing the target-set absorption spectrum with a minimal sample thickness. Active acoustic metamaterials have also demonstrated the capability to tune bandgaps as well as to alter property of resonances in real time through stiffening of the spring constants, in addition to the PT symmetric acoustics that can achieve unprecedented functionalities. These emergent directions portend the transitioning of the field from the stage of novelty demonstrations to imminent applications of some acoustic metamaterials to select real-world problems, supported by an active research endeavor that continues to push the boundary of possibilities.
UR - http://hdl.handle.net/10754/626878
UR - http://aip.scitation.org/doi/10.1063/1.5007682
UR - http://www.scopus.com/inward/record.url?scp=85038815658&partnerID=8YFLogxK
U2 - 10.1063/1.5007682
DO - 10.1063/1.5007682
M3 - Article
AN - SCOPUS:85038815658
VL - 123
SP - 090901
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 9
M1 - 090901
ER -