  As two-dimensional metamaterials, metasurfaces open up new avenues for
designing static planar optics. However, the dynamic modulation of metasurfaces
in the optical band is required for practical applications. The existing
dynamic devices rarely utilized the polarization manipulation capability of
metasurfaces. Here, we demonstrate an electrically tunable multifunctional
metasurface in the visible range by integrating birefringent liquid crystals
(LCs) with all-dielectric metasurfaces based on a novel packaging scheme. By
combining the helicity-dependent geometric phase of the metasurface and the
polarization control ability of LC molecules, continuous intensity tuning and
switching of two helicity channels are realized. Electrically tunable
single-channel switchable metaholograms, multicolor multiplexed metaholograms,
and dynamic varifocal metalenses are designed to verify the concept. The
exploration of polarization control in dynamic tuning can pave the way for
dynamic metasurface devices in various applications, such as space light
modulators, light detection and ranging systems, and holographic displays.
