Study on the excitation and propagation characteristics of THz-wave surface plasmon polaritons on the surface of semiconductor

Abstract

In the paper, the excitation and propagation characteristics of terahertz (THz) wave surface plasmon polaritons (SPPs) at the interfaces of semiconductors (InAs, InP, GaAs) and air are presented. By analysing the confinement strength of surface plasmon and its propagation length with frequency changing, we demonstrate that the confinement strength of surface plasmon and its propagating length are a trade-off. Furthermore, the effect of temperature variation on the propagation characteristics of SPPs wave at the surface of intrinsic semiconductor InSb is presented. Calculations show that the surface plasma frequency goes higher with increasing temperature, corresponding to the enlargement of carrier concentration of semiconductor. The factor of confinement strength decreases while the propagation length of SPPs increases with increasing temperature under a certain excitation THz wave. This will provide a valuable reference for the design and optimisation of THz wave surface plasma devices.