Hybrid silicon/phase-change metasurfaces and nanoantennas for active nanophotonics

All-dielectric metasurfaces and nanoantennas offer unprecedented flexibility and efficiency of manipulation of light at the nanoscale. Still, the functionality of conventional dielectric-based devices is fixed-by-design, i.e. the response is locked-in at the fabrication stage. To address the challenges offered by modern nanophotonics, active, dynamic and reconfigurable control of such structures is required. Here, we demonstrate active all-dielectric devices enabled by embedding subwavelength chalcogenide phase-change material inclusions in the volume of main silicon nanoresonators. We validate the concept via the design and development of a metasurface for active spectral filtering in the near infrared and a subwavelength nanoantenna providing complete switching of surface plasmon-polariton directivity pattern.