SURFACE PLASMON POLARITON EXCITATION IN QUANTUM TUNNELLING JUNCTIONS

Abstract

This thesis presents an experimental and theoretical study of surface plasmon polariton excitation in quantum tunnelling junctions, focussing on the excitation process and outcoupling to daughter modes that can be used for a myriad of applications involving optoelectronic functionality and waveguiding. We focus on two systems -- one system that supports a cavity SPP mode in the most simple metal-insulator-metal geometry and one that does not support a cavity mode but directly excites an interfacial SPP in a metal-insulator-semiconductor system. The optical local density of states is analytically calculated for each system indicating energy decay pathways, and daughter mode outcoupling pathways are identified. We demonstrate a thorough characterisation of SPP excitation in quantum tunnelling junctions through a combination of real-plane, back focal-plane and spectral imaging that has not been undertaken before, and demonstrate the order of mode excitation in different geometries and the physical properties that SPP excitation depends on.