Transforming light with optical metamaterials

Recent progress in developing optical metamaterials allows unprecedented control over the flow of light at both the nano- and macroscopic scales. Metamaterials (MMs) are rationally designed artificial materials with versatile properties that can be tailored to fit almost any practical need and thus go well beyond what can be obtained with “natural” materials. We review the exciting field of optical metamaterials and discuss the recent progress in developing tunable and active MMs, nanolasers, artificial optical magnetism, loss-free negative-index MMs, broadband cloaking, and new means for engineering the photonic density of states with MMs. Finally, a powerful paradigm of shaping space for light with transformation optics, which can enable a family of new applications ranging from a flat magnifying hyperlens to an invisibility cloak, will be also discussed. Mathematical problems and challenges related to these recent developments will be emphasized.