Invisibility has been solely the domain of science fiction for more than a century. However, it was discovered 10 years ago that there is a solution to this problem lurking in classical wave propagation theory. Work led by Prof. Sir John Pendry showed that electromagnetic wave scattering from an object can, in theory, be eliminated by surrounding it with a shell with the right material properties. Moreover, despite initial suggestions to the contrary, several groups (including mine) soon showed how this concept can be extended to sound waves and other types of waves as well. I will describe the coordinate-transformation theory behind these solutions, the methods designing and fabricating the artificial materials (or metamaterials) that have the necessary but unusual properties, our experimental demonstrations of acoustic cloaking that helped prove that the concept is feasible using mechanical metamaterials, and the challenges and practical difficulties that remain before this idea can yield devices or materials that achieve what most people think of as invisibility.
About the Speaker
Steven A. Cummer is currently Professor of Electrical and Computer Engineering at Duke University. He received his Ph.D. in Electrical Engineering from Stanford University in 1997 and spent two years at NASA Goddard Space Flight Center as a National Research Council postdoctoral research associate before joining Duke University. He was also a Visiting Fellow at the University of Otago in New Zealand in 2009. His current research interests span a variety of theoretical and experimental topics in complex materials for controlling electromagnetic and acoustic wave propagation, and in geophysical remote sensing with a focus on lightning and atmospheric electricity. He has written or coauthored more than 200 papers in refereed journals, is a Fellow of the IEEE and a Fellow of the American Geophysical Union, and received a Presidential Early Career Award for Scientists and Engineers (PECASE) in 2001.
Hosts: Professors Gaurav Bahl and Katie Matlack