Gain enhancement effect of surface plasmon polaritons on terahertz stimulated emission in optically pumped monolayer graphene

摘要

Giant gain enhancement effect of surface plasmon polaritons (SPPs) on terahertz (THz) stimulated emission in optically pumped monolayer graphene has been experimentally studied. We observed the spatial distribution of the THz probe pulse intensities under linear polarization of optical pump and THz probe pulses. It was clearly observed that an intense THz probe pulse was detected only at the area where the incoming TM mode THz probe pulse being capable of exciting the SPPs. The observed gain factor ∼50 is in fair agreement with theoretical calculations.