Remote excitation and remote detection of a single quantum dot using propagating surface plasmons on silver nanowire

Using propagating surface plasmons (SPs) on a silver nanowire (NW), we demonstrate that a focused laser light at the end of the silver NW can excite a single quantum dot (QD) microns away from the excitation spot. The QD—NW interaction allows the excited QD convert part of its energy into propagating SPs, which then can be detected at remote sites. Simultaneous multi-QD remote excitation and remote detection can also be realized. Furthermore, the tight confinement of the propagating SPs around the NW surface enables the selective excitation of QDs very close in space, which cannot be realized under the conventional excitation condition. This remote excitation and remote detection approach may find applications in optical imaging and the sensing of chemical and biological systems.