Nonvolatile switchable electromagnetically induced transparency in terahertz range

The terahertz frequency range has attracted significant interest for its potential in applications such as high-speed communication, sensing, and imaging. However, the dynamic control of terahertz waves remains a challenge. Here, we present a switchable metasurface incorporating the Ge-Sb-Te (GST) phase-change material, designed to achieve switchable electromagnetically induced transparency (EIT) in the terahertz frequency range. The metasurface features an array of gold stripes on a thin GST sublayer, with the quasi-BIC-related EIT mode arising from a hybrid symmetry-protected Friedrich-Wintgen supercavity mode. By carefully adjusting the geometric parameters of the gold stripes, the EIT bandwidth can be precisely tuned through the controlled asymmetry. The phase transition of GST induces a significant change in the metasurface electrical properties, enabling robust nonvolatile switching between transparent and opaque states of the device. Both theoretical analysis and experimental validation confirm the efficacy of this design for dynamic modulation in the terahertz regime, demonstrating its potential for advanced terahertz photonic applications.