Science 343, 160–163 (2014)

Light can process information at a much higher rate than electrons. But electronics has the advantage of being more compact, which makes it the technology of choice for computation. Alexandre Silva and colleagues now show, however, that engineered materials can perform mathematical functions on a scale much smaller than bulky optical components, down to the wavelength of light itself.

Metamaterials are arrays of sub-wavelength structures that can interact with the electric and magnetic components of light in a way that atoms do not. Thus, scientists can design metamaterials with far more complex optical properties than those of natural materials.

Silva et al. consider a burst of light in which information is encoded in the pulse shape, and show theoretically that a metamaterial thin film can alter this shape as the light passes through so that the output pulse gives the correct response to a mathematical function. From this, they simulate a metamaterial that can perform basic image-manipulation processes, such as spatial differentiation, integration and convolution.