Terahertz meta-absorber with tunable single- and dual-resonance characteristics

A design of tunable terahertz (THz) meta-absorber (TMA) is proposed, which is composed of a periodic Al cross-shaped resonator suspended on bottom Al mirror layer. The electromagnetic responses of TMA can be manipulated between single- and dual-resonance. TMA shows polarization dependent and independent characteristics. Moreover, the flexibility and applicability of TMA are highly improved as it exhibits the linear red-shifting of resonances by increasing the environmental refraction index. The highest sensitivity is 3.05 THz/RIU. This design of tunable TMA provides a useful method for the applications in solar cells, optical switching, imaging, energy harvesting, and high-sensitive sensing in the THz-wave optoelectronics fields.