Switchable metasurface with double phase distributions for wavefront manipulation

We designed a switchable metasurface for wavefront manipulation by employing vanadium dioxide (VO2), which can convert the circular polarized wave to its cross-polarized wave. With the change of conductivity of VO2 at different temperatures, the metasurface can exhibit two different phase distributions at the same targeted frequency. The two phase distributions can be easily attained by rotating two rings of the unit elements. Next, based on the metasurface, we designed focal length switchable metalens and generated vortex beam carrying OAM in different modes controlled by temperature. Different from the traditional multifunctional integrated metasurfaces, the designed metasurface has a dynamic tunable feature, providing great flexibility in wavefront manipulation.