Steve Africk holds A.B. and Ph.D. degrees in Physics from Cornell and Brown Universities and has been working in acoustics since joining BBN in 1972. He was a founder and later president of Atlantic Applied Research Corp and he became a full time employee of Acentech in 2007. Steveâ€™s work with underwater vehicles has focused on applications of acoustic materials and design of treatments for sonar noise control and acoustic signature reduction. His background led him to the study of acoustic cloaking by metamaterials for the Office of Naval Research. Steve has also been working with MIT to develop an ultrasonic technique for characterizing nanoparticles.
Once only in the toolbox of the Romulans, the Klingons, and Harry Potter, serious science on the possibility of cloaking objects began about 7 years ago. At that time, it was discovered that arbitrary bending of electromagnetic fields and waves was possible given materials with the right kind of properties. Using this technology, it is possible to design a â€œmetamaterialâ€ to create an enclosure that perfectly absorbs incident sound, guides it around the object, and allows it to exit the cloak on the opposite side so that the acoustic field there is exactly as it would have been in the absence of the object, thereby rending it invisible to monostatic and bistatic sonar. Acentech has been developing an approach to cloaking based on simple dynamic oscillators since 2008, but fabrication difficulties have led to consideration of a different type of design. Whether the Navy will continue this project to investigate these alternatives is, currently, cloaked in uncertainty.