October 5, 2010
The acoustic "sisters" of electromagnetic invisibility cloaks are long-sought devices that could defeat sonars. The existence of two types of acoustic waves in elastic media, however, makes acoustic cloaking very hard to achieve. The paper by Yaroslav Urzhumov and co-workers, published recently in the New Journal of Physics (July 12, 2010), is the first report on the feasibility of building an acoustically undetectable elastic cloak.
Acoustic cloaking transformations from attainable material properties, Urzhumov, Yaroslav A., Ghezzo F., Hunt J., and Smith D. R. , New Journal of Physics, 07/2010, Volume 12, Number 7, p.073014, (2010)