title: Theoretical requirements for broadband perfect absorption of acoustic waves by ultra-thin elastic meta-films.
abstract: We derive and numerically demonstrate that perfect absorption of elastic waves can be achieved in two types of ultra-thin elastic meta-films: one requires a large value of almost pure imaginary effective mass density and a free space boundary, while the other requires a small value of almost pure imaginary effective modulus and a hard wall boundary. When the pure imaginary density or modulus exhibits certain frequency dispersions, the perfect absorption effect becomes broadband, even in the low frequency regime. Through a model analysis, we find that such almost pure imaginary effective mass density with required dispersion for perfect absorption can be achieved by elastic metamaterials with large damping. Our work provides a feasible approach to realize broadband perfect absorption of elastic waves in ultra-thin films.
authors.affiliation: College of Physics, Optoelectronics and Energy &Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
authors.forename: Yuetao
authors.initials: Y
authors.lastname: Duan
authors.affiliation: College of Physics, Optoelectronics and Energy &Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Luo
authors.affiliation: College of Physics, Optoelectronics and Energy &Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
authors.forename: Guanghao
authors.initials: G
authors.lastname: Wang
authors.affiliation: College of Physics, Optoelectronics and Energy &Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
authors.forename: Zhi Hong
authors.initials: ZH
authors.lastname: Hang
authors.affiliation: College of Physics, Optoelectronics and Energy &Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Hou
authors.affiliation: School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Jensen
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
authors.forename: Ping
authors.initials: P
authors.lastname: Sheng
authors.affiliation: College of Physics, Optoelectronics and Energy &Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Lai