Mikhail F. Limonov is a leading research scientist at the Ioffe Physical-Technical Institute of the Russian Academy of Sciences and a research fellow at the National Research University of Information Technologies, Mechanics and Optics. He has worked for more than 30 years in the optical research community, focusing on various dielectrics, fullerenes, zeolites, superconductors, and photonic crystals. Richard M. De La Rue is a visiting professor at the University of Malaya and an honorary senior research fellow at the University of Glasgow. He is a fellow of the IEEE, OSA, IET, RSE, and RAEng. His research on photonic-crystal, nanophotonic, and photonic-wire structures has focused on both waveguide microcavities and metamaterials.