Tunable silicon-based all-dielectric metamaterials with strontium titanate thin film in terahertz range.

Silicon-based all-dielectric metamaterials (SAMs), with advantages like low loss and simple structure, are attracting more and more attention. However, SAMs usually suffer from narrow bandwidth and low tunability, and thereby their applications are seriously impeded. In this work, we propose and experimentally demonstrate a tunable SAMs in terahertz (THz) ranges by covering the SAMs with a layer of active medium, strontium titanate (STO). It shows that the THz responses of SAMs can be thermally tuned due to the temperature-dependent permittivity of STO. This work provides a convenient route to tunable SAMs from THz to optical ranges.