One-way Electromagnetic Mode Guided By The Mechanism Of Total Internal Reflection At THz Frequencies

One-way propagation and related nonreciprocal components are one of the research hotspots in the terahertz(THz)science and technology.The one-way electromagnetic(EM)modes previously reported are all surface waves.Here we report that one-way EM mode guided by the mechanism of total internal reflection(TIR)can be realized in the THz regime.One-way mode of this type is not a surface wave.The guiding system under our consideration is a layered metal-dielectric-semiconductor structure,and its dispersion relation is derived analytically.It is shown that when the thickness of the dielectric layer in the system is less than a critical value,TIR modes with higher orders vanish within the semiconductor bandgap and only the fundamental TIR mode that is one-way propagating is preserved.The analytical expression for that critical thickness is derived.By the numerical simulation,it is shown that the one-way TIR mode is immune to backscattering.Moreover,it is also shown that compared to one-way magnetoplasmons,the TIR one-way mode can be much effectively coupling with the fundamental mode of conventional optical waveguide.Based on the TIR mode,the one-way waveguide is easy to be compatible with conventional waveguide technology,and this is beneficial for it to practical applications.