Resolving single plasmons generated by multiquantum-emitters on a silver nanowire.

Surface plasmons, the collective oscillations of electrons at metal surface, provide the ability to enhance the weak interaction between individual quantum emitters and photons for quantum information applications. The generation of single plasmons by coupling silver nanowire with single quantum emitters opens the prospects of using quantum optical techniques to control single surface plasmons and designing novel quantum plasmonic devices. However, the real applications will deal with multiple plasmons generated from multiple quantum emitters. Here we report the first experimental demonstration of resolving single plasmons generated by a pair of quantum dots (QDs) on a silver nanowire waveguide. The accurate positions of the two QDs with separation ranging from micrometers to 200 nm within the diffraction limit are determined by using super-resolution imaging method. The efficiency of plasmon generation due to the exciton-plasmon coupling is obtained for each QD. Our research takes a crucial step toward the experimental study of coupled systems of multiple quantum emitters and plasmonic waveguides and would shed new light on the study of light-matter interactions for potential quantum optics and quantum information applications.