Excitation and modulation of long-range surface plasmons based on InSb multilayer structure

We proposed an Ag-based multilayer InSb and SiO2 system in the terahertz region. Based on the surface plasmon polariton (SPP) interaction among each interface, the spontaneous emission of a dipole in multilayer systems supporting SPP and waveguide modes is theoretically studied. It found that the coupling efficiency of long-range SPP (LRSPP) is about 78% with a propagation length of up to 28.25 mm. The thermally tunable characteristics of InSb enable LRSPP devices to be realized with adjustable coupling efficiency. Our work could be applied as a future guide for integrated plasmonic device design.