Design of electrostatically tunable terahertz metamaterial with polarization-dependent sensing characteristic

Abstract

We present a design of MEMS-based tunable terahertz (THz) metamaterial (TTM) with polarization-dependent sensing characteristic. The MEMS-based TTM device is reconfiguration by using two electrostatic comb-drive actuators, which exhibits tunable dual-band resonances in both transverse electric (TE) mode and transverse magnetic (TM) modes. The tuning ranges of free spectra ranges are 42 GHz and 82 GHz for TE and TM modes, respectively by increasing the gap between the left and right semicircle-shaped ring resonators. The electromagnetic responses of the proposed MEMS-based TTM device can be switched between dual-resonance and triple-resonance by changing the distance between the left and right semicircle-shaped ring resonators along y-axis direction. These results indicate MEMS-based TTM device shows polarization-sensitive and switching characteristics. MEMS-based TTM device is particularly sensitive to the environmental refraction index, and there is a linear relationship between the shift of resonant frequency and the change of refraction index. The sensitivity is 0.186 THz/RIU while the maximum figure of merit and quality factor reach 208 and 248, respectively at the first TE resonance. These outstanding and unique results of MEMS-based TTM device provide an effective approach for the design of highly linear and sensitive gas and environmental applications.