Plasmon-assisted controllable excitation of single quantum dots on a metal nanowire

Abstract

The hybrid systems of multiple quantum emitters coupled with plasmonic waveguides provide promising building blocks for the future integrated quantum nanophotonic circuits. The techniques that can selectively excite adjacent quantum emitters in a diffraction-limited area are of great importance for studying the plasmon-mediated interaction between quantum emitters and manipulating the generation and propagation of single plasmons in nanophotonic circuits. We show that by modulating the electric field on the nanowire using the interference of surface plasmons, multiple quantum dots coupled with a silver nanowire can be controllably excited. We experimentally demonstrate the selective excitation of two quantum dots with a separation distance of about 100 nm. Our work provides a new kind of optical excitation and characterization method overcoming the diffraction limit, and adds a new tool for studying and manipulating single quantum emitters and single plasmons for quantum plasmonic circuitry applications.