Reconfigurable near-IR metasurface based on Ge 2 Sb 2 Te 5 phase-change material

A reconfigurable metasurface made of Ge2Sb2Te5 phase-change material was experimentally demonstrated in the 1.55 μm wavelength range. A nanostructured Ge2Sb2Te5 film on fused silica substrate was optimized to switch from highly transmissive (80%) to highly absorptive (76%) modes with a 7:1 contrast ratio in transmission independent of polarization, when thermally transformed from the amorphous to crystalline state. The metasurface was designed using a genetic algorithm optimizer linked with an efficient full-wave electromagnetic solver.