Electromagnetic and Acoustic Cloaking

Although this section is called electromagnetic and acoustic cloaking, it is really about more general concepts called transformation optics (or transformation electromagnetic) and transformation acoustics. My group has been involved in research on how the coordinate transformation invariance of certain wave equations can be exploited to produce specifications for novel materials and devices. Electromagnetic and acoustic cloaking, in which a material shell is designed to bend incident waves smoothly around an object and also fill in the shadow region, thereby rendering it effectively invisible, is just one application (albeit the most interesting) of these powerful concepts.

We have produced some important results in these fields, including the first full wave simulations of the electromagnetic version of these materials which demonstrated their experimental feasibility. We were also the first to show that the transformation concept could be applied to acoustic waves, thereby showing that acoustic cloaking was possible. More recently we also designed, built, and experimentally demonstrated an acoustic cloaking shell in air.

Some of Our More Important Papers on Transformation Optics and Transformation Acoustics

One of the first experimental demonstrations of acoustic cloaking: Popa, B.-I., L. Zigoneanu, and S. A. Cummer (2011),

**Experimental acoustic ground cloak in air**, Phys. Rev. Lett., v. 106, 253901. [pdf reprint]

A complete, first-principles derivation of transformation acoustics theory: Cummer, S. A., M. Rahm, and D. Schurig,

**Material parameters and vector scaling in transformation acoustics**, New J. Phys., v. 10, 115025, 2008. [pdf reprint]

The first theoretical work showing the validity of transformation acoustics: Cummer, S. A., and D. Schurig,

**One path to acoustic cloaking**, New Journal of Physics, v. 9, 45, 2007. [pdf reprint]

Numerical simulations of an electromagnetic cloaking shell, showing that the concept could work: Cummer, S. A., B.-I. Popa, D. Schurig, D. R. Smith, and J. B. Pendry,

**Full-wave simulations of electromagnetic cloaking structures**, Physical Review E, 74, 036621, 2006. [pdf reprint]