Ultrasonic metamaterials with negative modulus

Fang, Nicholas and Xi, Dongjuan and Xu, Jianyi and Ambati, Muralidhar and Srituravanich, Werayut and Sun, Cheng and Zhang, Xiang. (2006) Ultrasonic metamaterials with negative modulus. Nature Materials, 5 (6). pp. 452-456. ISSN 1476-1122

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Abstract

The emergence of artificially designed subwavelength electromagnetic materials, denoted metamaterials1, 2, 3, 4, 5, 6, 7, 8, 9, 10, has significantly broadened the range of material responses found in nature. However, the acoustic analogue to electromagnetic metamaterials has, so far, not been investigated. We report a new class of ultrasonic metamaterials consisting of an array of subwavelength Helmholtz resonators with designed acoustic inductance and capacitance. These materials have an effective dynamic modulus with negative values near the resonance frequency. As a result, these ultrasonic metamaterials can convey acoustic waves with a group velocity antiparallel to phase velocity, as observed experimentally. On the basis of homogenized-media theory, we calculated the dispersion and transmission, which agrees well with experiments near 30 kHz. As the negative dynamic modulus leads to a richness of surface states with very large wavevectors, this new class of acoustic metamaterials may offer interesting applications, such as acoustic negative refraction and superlensing below the diffraction limit.

Item Type: Article
Additional Information: Reprinted by permission from Macmillan Publishers Ltd: [Nature Materials] ("Ultrasonic metamaterials with negative modulus", Fang N. et al., Nature Materials 5, 452 - 456), copyright (2006)
Uncontrolled Keywords: Electromagnetic materials, negative modulus
Collections: Nanomanufacturing Research Collection
Depositing User: Moureen Kemei
Date Deposited: 24 Mar 2010 21:16
Last Modified: 24 Mar 2010 21:16
URI: http://eprints.internano.org/id/eprint/365

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