Computational Metamaterials Optical signal processing of light waves can represent certain mathematical functions and perform computational tasks on signals or images in an analog fashion. However, the complex systems of lenses and filters required are bulky. Metamaterials can perform similar optical processing operations but with materials that need only be a wavelength thick. Silva et al. (p. 160 ; see the Perspective by Sihvola ) present a simulation study that shows how an architecture based on such metamaterials can be designed to perform a suite of mathematical functions to create ultrathin optical signal and data processors.