Acoustic total transmission and additional modes in the metamaterials embedded with defects

Erliang Ding,Xiaozhou Liu,Yifeng Li,Yangyang Wang

doi:10.1063/1.4967426

Abstract

Total reflection or transmission of waves has been explored extensively in different types of zero-index metamaterials (ZIMs). Almost all previous studies have shown that only monopole modes are excited inside the defects if they are cylindrical. However, the underlying physics for excited modes inside defects is wrongly ignored. In this work, we reveal that there is not only a monopole mode but also additional higher modes excited inside cylindrical defects by a system of two-dimensional waveguides. Actually, the total acoustic transmission and additional higher modes can occur simultaneously in a ZIM waveguide embedded with defects. We reveal the physical mechanism of excited higher modes, which will perfect the current perception of the excited modes in the acoustic metamaterials inside defects. Moreover, numerical simulations are carried out to demonstrate our finding concerning the additional modes.

Highlights

Metamaterials,[1,2,3,4,5] as artificial materials possessing unusual parameters, have drawn extensive attention
We describe the physical mechanism of how to excite higher modes theoretically in the defects through the zero-index metamaterials (ZIMs), and we show the concurrence of higher modes and monopole modes when total transmission occurs
If Jm (k21R1) = 0, m ≥ 2 and iωη1S0/2hκ1 + iπη1R1/hJ1(k21R1) η21J0(k21R1) = 0 are satisfied, tripole or even higher modes can be excited in the impedance density-near-zero metamaterials (IDNZMs) when total transmission occurs

Summary

Introduction

Metamaterials,[1,2,3,4,5] as artificial materials possessing unusual parameters, have drawn extensive attention. There is only dipole mode excited in addition to the monopole mode when total transmission occurs. When total transmission occurs, the dipole mode is not excited for the mismatched impedance density-near-zero metamaterials (IDNZMs).

Results

Conclusion