Three-dimensionally reconfigurable focusing of laser by mechanically tunable metalens doublet with built-in holograms for alignment

Abstract Metalenses have potential to replace various bulky conventional optical elements with ultrathin nanostructure arrays. In particular, active metalenses reconfigurable focusing capability attracted considerable interest from the academic and industrial communities. However, their tuning range is currently restricted by limited material properties fabrication difficulties. Here, a hybrid system capable of three-dimensional relocation focal spot proposed experimentally demonstrated. The comprises mechanically actuated passive metalens doublet that can be easily fabricated commonly available materials processes. An incident laser focused desired point in space simply rotating two or changing separation. addition, exploiting polarization-multiplexing metasurfaces, hologram incorporated guide rotational positional alignment metasurfaces. ease provided this approach could widen its application many practical fields.