Hybrid amorphous strontium titanate and terahertz metasurface for ultra-sensitive temperature sensing.

In this study, a hybrid amorphous strontium titanate (STO) and terahertz metasurface were studied. Because of the excellent physical properties of amorphous STO, such as its dielectric properties and high transmittance in the terahertz region, it plays a core role in realizing a novel terahertz (THz) temperature sensor with high performance in the temperature range of 500-608 K. A blue shift of the absorption peaks appeared for the THz wave as the temperature increased, which confirmed the temperature-sensing function. The physical mechanisms underlying this phenomenon were also investigated. After optimization, the best THz temperature sensor with a sensitivity of 2.08 GHz/K was obtained, in which the thickness of the amorphous strontium titanate film was approximately 0.36 µm. This study provides a new opportunity for amorphous STO materials to be applied in THz sensors and demonstrates the realization of amorphous STO-based THz temperature sensors with high performance, low cost, and simple processes.