A new class of artificial materials called metamaterials may one day be used to create ultrapowerful microscopes, advanced sensors, improved solar cells, computers that use light instead of electronic signals to process information, and even an invisibility cloak. In a Perspectives piece in this week's issue of the journal Science, Caltech's Harry Atwater and Purdue University colleague Alexandra Boltasseva describe advances in a particular subtype of these materials—plasmonic metamaterials.