InSb-Enhanced Thermally Tunable Terahertz Silicon Metasurfaces

Terahertz silicon-based all-dielectric metasurfaces have attracted enormous attention for their promising applications. In practice, however, their tuning ability has been limited by the stability of silicon. Herein, we propose a new way to realize thermally tunable silicon metasurfaces in the terahertz region based on InSb film. To verify the feasibility of this method, a tunable all-dielectric metasurface absorber based on hybrid dielectric waveguide resonance is designed and demonstrated. The absorber consists of sub-wavelength silicon cylinders on the polydimethylsiloxane (PDMS) substrate, and an ultra-thin InSb film is deposited on it to achieve tunability. Meanwhile, by employing the other free-standing grating structure, the universality of this method is demonstrated. Notably, when the temperature increases from 300 to 400 K, the resonance shift in the grating structure can reach 0.091 THz, and good amplitude stability in the transmission spectrum is achieved. With advantages like fine tunability and easy fabrication, these all-dielectric metasurfaces may have great potential in THz high efficiency devices.