Controlling mass and energy diffusion with metamaterials

Metamaterials are artificially patterned structures designed to behave as artificial materials with novel properties. A popular application is controlling electromagnetic waves with subwavelength patterning, leading to properties like negative indices of refraction. Metamaterials can also control diffusion processes, which are different from wave propagation. This review describes metamaterials in diffusive systems in terms of their underlying physics, the theory used to describe them, and their potential applications in areas such as heat management, drug transport, and particle separation.