Unidirectional Cloaking Based on Metasurfaces with Balanced Loss and Gain

Rendering things invisible has turned out to be in the domain of science, not magic. The authors offer an approach to cloaking based on a simple conformal surface wrapped around the object of interest. Their theory shows that by covering the object with a stealth surface on the illuminated side, and a time-reversed version of the same surface on the shadowed side, one can realize ideal cloaking, independent of the size of the object, in a robust, broadband, ultrathin, and lossless technology.