Tunable terahertz double split-ring metamaterial with polarization-sensitive characteristic

We propose a design of tunable double split-ring metamaterial (DSRM) in the terahertz (THz) frequency range. It is composed of a H-shaped resonator sandwiched by two face-to-face split-ring resonators (SRRs) on silicon on insulator (SOI) substrate. The electromagnetic responses of DSRM can be manipulated between single-resonance and dual-resonance by changing the incident polarization light, which shows polarization sensitive characteristic. DSRM exhibits a tunable function in the frequency range of 0.16 THz to 0.21 THz through enlarging the gap within two SRRs at TE mode. DSRM also shows stable characteristic by changing the distance between two faceto-face SRRs at TE and TM modes. Furthermore, to enhance the flexibility and applicability of DSRM, it is exposed on the surrounding environments with different refraction indexes. The correction coefficients are 0.997 for DSRM at TE and TM modes. These results show that DSRM exhibit the linear red-shifting of resonances by increasing the environmental refraction index. This work paves a way to the possibility of metamaterial devices with great tunability and polarization-dependence characteristics in the sensing applications.