Tunable lattice-induced transparent metasurface for dynamic terahertz wave modulation.

Tunable metasurfaces offer a promising avenue for dynamically modulating terahertz waves. Phase-change materials are crucial in this dynamic modulation, enabling precise and reversible control over the electromagnetic properties of the metasurfaces. In this study, we designed and experimentally fabricated a tunable lattice-induced transparent metasurface. This metasurface comprises two gold rod resonators exhibiting different periodic distributions, each supporting an electric dipole resonance at 2.03 THz and a surface lattice resonance at 1.51 THz, respectively. By combining these structures, we realize lattice-induced transparency. Simulation results show that the phase change of Ge ₂ Sb ₂ Te ₅ modulates these resonances, with the crystalline state significantly weakening their resonance strength intensity. The maximum modulation depth of the lattice-induced transparency peak can reach 44.4%. Experimental results of laser-induced GST phase changes confirm a modulation depth of 42.4%. This innovative metasurface design holds promise for applications in terahertz communication systems.