Plasmonic nanolasers based on graphene-insulator-metal platform

The development of laser miniaturizing is never stop; several kinds of approaches such as microdisk lasers and nanowire lasers, have been exploited to scale down the sizes of cavity by using surface plasmons in replacement of photonic resonance in the laser cavity. Graphene is a membrane with thickness of only one atom and the carrier mobility can be as high as about 15000 cm² /V. s. Until now graphene has been widely used for many optoelectronics applications, for example, ultrafast photodetector, modulator, biosensor, transparent electrode and so on. As far as plasmonic laser is concerned, since the insulator layer on the metal structure is required to be very thin, it seems to be feasible to add a single-layered graphene in between the nanowire and metal while preserving the capability of forming surface plasmon polariton (SPP). Besides, we would like to take advantage of good electrical property of graphene to make a plasmonic nanolaser which can be modulated by externally applied current. By adding graphene on the insulator can form a versatile platform, called graphene-insulator-metal (GIM) structure, that can modulate the plasmonic wave characteristics. In this study, we successfully fabricated and demonstrated the SPP nanolaser on GIM structure. The lasing threshold of ZnO nanowire on aluminum with graphene was lower than that without graphene. It was attributed to the changes of plasmon frequency of metal resulting from the induced electrons or holes by graphene.