Tunable wave plates based on phase-change metasurfaces
Dong‐Qin Zhang, Fangzhou Shu, Zhiwei Jiao, Hong‐Wei Wu
Abstract
Wave plates based on metasurfaces have attracted intensive attention over the past decade owing to their compactness and design flexibility. Although various wave plates have been designed, their working wavelengths are fixed once they are made. Here we present a study on tunable wave plates based on phase-change metasurfaces made of Ge 2 Sb 2 Te 5 nanopillar structures. The Ge 2 Sb 2 Te 5 nanopillars can work as a high-efficiency transmissive half- or quarter-wave plate depending on their structural parameters. The working wavelength of wave plate can be tuned via the phase transition of Ge 2 Sb 2 Te 5 . Moreover, the polarization state of the transmitted light at a fixed wavelength can be modified by changing the crystallinity of Ge 2 Sb 2 Te 5 . The features suggest that tunable wave plates may have applications in optical modulators, molecular detection, and polarimetric imaging.