Decay and propagation properties of symmetric surface plasmon polariton mode in metal–insulator–metal waveguide

Abstract

Decay and propagation properties of symmetric surface plasmon polariton (SPP) mode based on metal–insulator–metal (MIM) waveguide are investigated numerically. SPP mode is excited through a dipole embedded in Al2O3 layer of Au/Al2O3/Au structure. We demonstrate that the distance between the dipole and Al2O3/Au interface is an important tunable parameter to influence the decay properties. The electric/magnetic field intensity horizontal and vertical decay lengths of symmetric SPP mode are 19nm and 24nm, respectively. Moreover, the propagation length along Al2O3/Au interface of symmetric SPP mode depends on Al2O3 layer thickness. The maximal propagation length reaches 0.608μm with Al2O3 layer thickness of 100nm. These values can provide a theoretical reference for designing a high-performance SPP source using Au/Al2O3/Au structure.