Dynamic chiroptical responses in transmissive metamaterial using phase-change material

Abstract In this work, we numerically demonstrate tunable chiroptical responses in a transmissive asymmetrically split ring metamaterial composed of metal/phase change material Ge 2 Sb 2 Te 5 (GST)/metal multilayer stack. The pronounced optical contrast between the amorphous and crystalline GSTs results in a large frequency tuning range of both resonant asymmetric transmission and circular dichroism up to 38.7%. Additionally, the hybrid metamaterial can be employed to explore phase transition process between amorphous and crystalline GSTs via detecting polarization conversion or circular dichroism with low background noise since the resonant signal is quite sensitive to proportions of amorphous and crystalline GSTs. The polarization conversion efficiencies and resonant frequencies can be tuned via parameter study. This work pays a way towards the realization of GST-enabled dynamic polarization control in the optical region.