Proposed graphene nanospaser
Researchers in the USA have proposed a nanoscale device that could be capable of creating a localized, intense mid-infrared field. Vadym Apalkov and Mark Stockman from Georgia State University say that their ‘nanospaser’ would be useful for applications such as nanospectroscopy, nanolithography and nanoscopy. Their design consists of a nanopatch of graphene that supports plasmons atop a gain-providing stack of semiconductor quantum wells. The system of quantum wells is similar to that found at the heart of a quantum cascade laser. When driven electrically, the nanospaser should generate concentrated, coherent optical fields that localize near the surface of the graphene. Although optically excited spasers have already been reported, this device, if experimentally realized, would be the world’s first electrically pumped spaser.