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

TL;DR

This study investigates nanoscale gold wires on GaAs substrates that guide surface plasmon polaritons and can couple with embedded quantum dots, advancing integrated quantum plasmonic device development.

Contribution

It demonstrates the guiding of surface plasmon polaritons along subwavelength gold nanowires and their potential to couple with quantum dot emitters, supported by experimental and simulation results.

Findings

Surface plasmon polaritons propagate over 5-20 μm along 100 nm wide gold wires.

Finite difference time domain simulations confirm experimental observations.

Potential for coupling quantum dots to plasmonic modes in nanoscale devices.

Abstract

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 $5-20 \mu m$ along nanowires with a lateral dimension of only $\approx 100 nm$. Finite difference time domain simulations are used to corroborate our experimental observations and highlight the potential to couple proximal quantum dot emitters to propagating plasmon modes in such extreme sub-wavelength 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.