Tunable terahertz hybrid metamaterials supported by 3D Dirac semimetals

By utilizing the three-dimensional Dirac semimetal (DSM)-strontium titanate (SrTiO3, STO) elliptical hybrid metamaterials, the tunable Fano resonances were systematically analyzed in the THz regime, for example, the effects of asymmetric degrees, DSM Fermi levels, and operation frequencies. Interestingly, an obvious Fano peak is observed by introducing a displacement (asymmetric degree) between STO and DSM resonators. In particular, the amplitude modulation depth (MD) of the Fano transmission peak (reflection dip) is 49.5% (86.65%) when the asymmetric degree ranges from 0 to 20 mu m. Furthermore, on the condition that the asymmetric degree is larger than 10 mu m, the LC resonance is also excited with an extraordinary Q-factor of more than 25. Additionally, by modifying the Fermi level of DSM layer, the amplitude MD of Fano transmission peak (reflection dip) is 32.86% (67.26%). The results facilitate our understanding of the tunable mechanisms of DSM metamaterials and potentially promote the development of novel plasmonic devices, including filters, modulators and sensors.(c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

Tunable Fano resonances in the THz regime were analyzed using three-dimensional Dirac semimetal (DSM)-strontium titanate (STO) elliptical hybrid metamaterials, considering the effects of asymmetric degrees, DSM Fermi levels, and operation frequencies. An obvious Fano peak was observed by introducing a displacement between STO and DSM resonators, with an amplitude modulation depth of 49.5% for the transmission peak and 86.65% for the reflection dip. Additionally, modifying the Fermi level of DSM layer resulted in an amplitude modulation depth of 32.86% for the transmission peak and 67.26% for the reflection dip. These findings provide insights into the tunable mechanisms of DSM metamaterials and have implications for the development of plasmonic devices.