Active modulation of polarization-independent plasmon-induced transparency metasurfaces using phase change materials

Abstract

Plasmon-induced transparency (PIT) metasurfaces have emerged as a promising platform for applications in ultrasensitive detection and slow-light devices. The active control of PIT metasurfaces is particularly crucial for advancing these applications. In this study, we integrate the phase change material Ge2Sb2Te5 (GST) into the structural design of a polarization-independent metasurface, enabling the experimental realization of ultra-large depth modulation of PIT peaks. This was achieved through direct thermal activation of the sample and laser-induced multilevel nonvolatile modulation, with a modulation range extending from 0% to 35.2%. The underlying mechanism for this significant modulation depth is attributed to the suppression of magnetic resonance by the GST phase transition, which is elucidated through analyses of multipolar scattering power, electric field distribution, and magnetic field distribution. The proposed terahertz metasurface presents a pathway for the development of optical switches and slow-light devices, with potential applications in advanced photonic systems.