  Achieving spatiotemporal control of light at high-speeds presents immense
possibilities for various applications in communication, computation,
metrology, and sensing. The integration of subwavelength metasurfaces and
optical waveguides offers a promising approach to manipulate light across
multiple degrees of freedom at high-speed in compact photonic integrated
circuit (PICs) devices. Here, we demonstrate a gigahertz-rate-switchable
wavefront shaping by integrating metasurface, lithium niobite on insulator
(LNOI) photonic waveguide and electrodes within a PIC device. As proofs of
concept, we showcase the generation of a focus beam with reconfigurable
arbitrary polarizations, switchable focusing with lateral focal positions and
focal length, orbital angular momentum light beams (OAMs) as well as Bessel
beams. Our measurements indicate modulation speeds of up to gigahertz rate.
This integrated platform offers a versatile and efficient means of controlling
light field at high-speed within a compact system, paving the way for potential
applications in optical communication, computation, sensing, and imaging.
