  Despite recent advances in active metaoptics, wide dynamic range combined
with high-speed reconfigurable solutions is still elusive. Phase-change
materials (PCMs) offer a compelling platform for metasurface optical elements,
owing to the large index contrast and fast yet stable phase transition
properties. Here, we experimentally demonstrate an in situ electrically-driven
reprogrammable metasurface by harnessing the unique properties of a
phase-change chalcogenide alloy, Ge$_{2}$Sb$_{2}$Te$_{5}$ (GST), in order to
realize fast, non-volatile, reversible, multilevel, and pronounced optical
modulation in the near-infrared spectral range. Co-optimized through a
multiphysics analysis, we integrate an efficient heterostructure resistive
microheater that indirectly heats and transforms the embedded GST film without
compromising the optical performance of the metasurface even after several
reversible phase transitions. A hybrid plasmonic-PCM meta-switch with a record
electrical modulation of the reflectance over eleven-fold (an absolute
reflectance contrast reaching 80%), unprecedented quasi-continuous spectral
tuning over 250 nm, and switching speed that can potentially reach a few kHz is
presented. Our work represents a significant step towards the development of
fully integrable dynamic metasurfaces and their potential for beamforming
applications.
