Optical study of lithographically defined, subwavelength plasmonic wires and their coupling to embedded quantum emitters.

We present an optical investigation of surface plasmon polaritons propagating along nanoscale Au-wires, lithographically defined on GaAs substrates. A two-axis confocal microscope was used to perform spatially and polarization resolved measurements in order to confirm the guiding of surface plasmon polaritons over lengths ranging from 5 to 20 μm along nanowires with a lateral dimension of only ≈ 100 nm. Finite difference time domain simulations are used to corroborate our experimental observations, and highlight the potential to couple proximal quantum emitters to propagating plasmon modes in such extreme subwavelength devices. Our findings are of strong relevance for the development of semiconductor based integrated plasmonic and active quantum plasmonic nanosystems that merge quantum emitters with nanoscale plasmonic elements.