Design and simulation of a GST-based metasurface with strong and switchable circular dichroism
Huan Jiang, Kangzhun Peng, Ying Cui, Jiyou Zhong, Hui Zhang, Yongyuan Jiang, Weiren Zhao
Abstract
Circular dichroism (CD) is required in the applications of biological detection, analytical chemistry, etc. Here, we numerically demonstrated large-range switchable CD by controlling the phase change of Ge 2 Sb 2 Te 5 (GST) in a zigzag array. At the amorphous state of GST (a-GST), the strong and dual-waveband CD effects are realized via the selective excitations of electric, magnetic, and toroidal resonances. With the transition from a-GST to crystalline state GST, CD strengths are tailored dynamically in large ranges. In detail, the CD magnitudes change by about 0.93 and the modulation depths exceed 94% at dual wavebands. The strong CD effects and large-range switch capability in the GST-based metasurfaces will boost the development of active chiroptical devices.