Breakthroughs in Photonics 2014: Phase Change Materials for Photonics

Materials that undergo an electronic phase change in a reversible manner open up new directions for research in light-matter interactions and photonic devices. The highly tunable dielectric properties, along with the spatial control of insulating and metallic domains, create photonic-crystal-like environments to control light propagation. In this brief overview, recent advances in photonics that utilize solid-state phase-change systems such as vanadium dioxide (VO₂) and chalcogenides are discussed. The controllable optical properties such as the refractive index and the optical conductance between two distinct phases in these materials pave the way for switchable photonic devices with memory. Furthermore, the intermediate states with the coexistence of two phases in the vicinity of phase transition in these materials behave as a tunable metamaterial with extraordinary optical properties that is promising for applications such as perfect absorbers.