Stealth technology, the idea of reducing the ability of the enemy to detect an object, has driven advances in military research for decades. Today, aircraft, naval ships and submarines, and missiles and satellites are often covered with radar-absorbent material, such as paint, to hide or cloak them from radar, sonar, infrared, and other detection methods. A cloak is a coating material that makes an object indistinguishable from its surroundings or undetectable by external field measurements.
Guoliang Huang, the James C. Dowell Professor in the Department of Mechanical and Aerospace Engineering, said these types of cloaking materials are mature, in the technical sense, because the properties of acoustic (radar, sonar) and optical waves (infrared) are well understood. However, Huang said little to no work has succeeded in solving the problem of cloaking for elastic waves in solid media, such as a seismic wave propagated through the ground. Recently, Huang, along with his former postdoc and students Assistant Professor Hussein Nassar and Research Assistant Professor Yangyang Chen, designed and created a new metamaterial, an artificially- structured material, that achieves “perfect” elastic material cloaking.