Metasurfaces have attracted increasing attention due to their powerful capabilities in manipulating electromagnetic (EM) waves. However, most of the existing designs are restricted to independent controls of either spatial waves or surface waves, while manipulating the reflected and transmitted spatial waves together with surface waves using a unified metasurface remains challenging. Here, we propose a mechanically reconfigurable and stacked metasurface that enables precise EM wave manipulations over full space. In the spatial-wave domain, the Pancharatnam-Berry phase characteristics of stacked meta-atoms can provide phase continuity for the integrated transmission-reflection wave control, allowing identical EM responses to be generated synchronously in both transmission and reflection regions. In the surface-wave domain, topologically protected EM wave propagation is realized by exploiting the analog valley Hall effect, complemented by an interlayer pseudo-spin converter, which enables robust and flexible surface-wave manipulations. Benefiting from its mechanically reconfigurable EM wave control capability across full space, the proposed metasurface supports multiple functionalities, including wireless communication, microwave security inspection, and physiological monitoring. This work establishes a new paradigm for the multidimensional EM wave manipulation using a unified platform and broadens the engineering potential of metasurfaces for integrated and multifunctional EM systems.
Chen et al. (Mon,) studied this question.