Control of the propagation distance of surface plasmons wave in terahertz spectrum

With the cutoff frequency of the surface wave in terahertz, the gradient depth of the metal grating was designed, and find that the cutoff frequency is 0.6 THz when the depth of the grating is 60 μm and 1.1 THz is nearly corresponding to the 120 μm. At the same time, the temperature controller semiconductor grating was designed. According to the dispersion characteristic of the semiconductor material (InSb) in terahertz region, the experience formula of the carrier concentration and mobility; equivalent medium theory of grating structure, it is shown that the propagation distance is proportion to the temperature in 270~300 K, which the propagation distance in 300 K is 2~3 times than the 270 K.