Sound Concentration, Enhanced Nonlinearities and Giant Nonreciprocal Response in Acoustic Metamaterials
Friday, October 4, 2013 4:00 p.m. in ETC 4.150
Professor Andrea Alù
Department of Electrical and Computer Engineering
The University of Texas at Austin
In this talk, I will discuss our recent progress and research activity in the field of acoustic metamaterials, focused on the general objective of enhancing sound-matter interactions in artificial materials. I will show how suitably designed metamaterials may be used to concentrate acoustic energy in small channels, producing giant nonlinear response, enhanced absorption and anomalous impedance matching. I will also discuss our recent theoretical and experimental results aimed at inducing acoustic isolation and large nonreciprocal sound transmission using metamaterial concepts. We achieve these effects by producing the acoustic equivalent of the Zeeman effect in a subwavelength meta-molecule consisting of a resonant ring cavity loaded by a circulating fluid. This concept has been used to realize a compact, fully linear, magnetic-free diode for airborne acoustic waves, which achieves up to 40 dB isolation at audible frequencies in a subwavelength device. Physical insights into these phenomena will be discussed during the talk.