The development of tunable devices is still a significant challenge for the evolving terahertz (THz) technology. Components allowing for agile manipulation of THz radiation, together with efficient low-cost emitters and sensitive detectors, are expected to greatly enhance the versatility of future applications. The development of metamaterials represents a promising opportunity allowing efficient control of THz radiation. In this work, we demonstrate a metamaterial exhibiting a tunable response in the terahertz domain, controlled by a bias electric field. The active part of the metamaterial consists of a periodic metallic pattern deposited on a thin epitaxially strained SrTiO3 film. The role of the metallic structure is two-fold: it gives rise to the metamaterial resonance and it enables applying a bias to the SrTiO3 film. The strained film exhibits a pronounced dependence of its permittivity on the bias, which exerts a strong influence on the resonance. Specifically, the resonance of our structure occurs near 0.5 THz and, upon applying a bias voltage of 55 V, a relative tunability of the resonance frequency of 19% was achieved at room temperature.
This work has been submitted to publication in Applied Physics Letters.