  Structural colors generated due to light scattering from static
all-dielectric metasurfaces have successfully enabled high-resolution,
high-saturation, and wide-gamut color printing applications. Despite recent
advances, most demonstrations of these structure-dependent colors lack
post-fabrication tunability. This hinders their applicability for front-end
dynamic display technologies. Phase-change materials (PCMs), with significant
contrast of their optical properties between their amorphous and crystalline
states, have demonstrated promising potentials in reconfigurable nanophotonics.
Herein, we leverage tunable all-dielectric reflective metasurfaces made of
newly emerged classes of low-loss optical PCMs, i.e., antimony trisulphide
(Sb$_2$S$_3$) and antimony triselenide (Sb$_2$Se$_3$), with superb
characteristics to realize switchable, high-saturation, high-efficiency and
high-resolution dynamic meta-pixels. Exploiting polarization-sensitive building
blocks, the presented meta-pixel can generate two different colors when
illuminated by either one of two orthogonally polarized incident beams. Such
degrees of freedom (i.e., material phase and polarization state) enable a
single reconfigurable metasurface with fixed geometrical parameters to generate
four distinct wide-gamut colors. We experimentally demonstrate, for the first
time, an electrically-driven micro-scale display through the integration of
phase-change metasurfaces with an on-chip heater formed by transparent
conductive oxide. Our experimental findings enable a versatile platform
suitable for a wide range of applications, including tunable full-color
printing, enhanced dynamic displays, information encryption, and
anti-counterfeiting.
