title: Acoustic metamaterial with negative modulus.
abstract: We present experimental and theoretical results on an acoustic metamaterial that exhibits a negative effective modulus in a frequency range from 0 to 450 Hz. A one-dimensional acoustic metamaterial with an array of side holes on a tube was fabricated. We observed that acoustic waves above 450 Hz propagated well in this structure, but no sound below 450 Hz passed through. The frequency characteristics of the metamaterial has the same form as that of the permittivity in metals due to the plasma oscillation. We also provide a theory to explain the experimental results.
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea.
authors.forename: Sam Hyeon
authors.initials: SH
authors.lastname: Lee
authors.forename: Choon Mahn
authors.initials: CM
authors.lastname: Park
authors.forename: Yong Mun
authors.initials: YM
authors.lastname: Seo
authors.forename: Zhi Guo
authors.initials: ZG
authors.lastname: Wang
authors.forename: Chul Koo
authors.initials: CK
authors.lastname: Kim