Multifunctional electrically switchable metalens

Here, we propose three all-solid-state, electrically switchable, transmissive, and multifunctional metalens arrays comprising tunable metal-oxide material BaTiO 3 (BTO) nanopillars with different structural parameters. To produce the required phase profile for each metalens, the rectangular nanopillars, as the unit cell of the BTO structure, are developed to support arbitrary combinations of two independent phase shifts (0−2 π ) with bias voltage states of 0 V and 60 V, at first. Second, the structure parameters of different functional metalens arrays are generated efficiently and accurately based on the dual-phase modulation characteristics of a single structure. Finally, we use the finite-difference time-domain method to simulate the three kinds of switchable metalenses. The results show that the three metalenses can realize the function of adjustable focus position, switchable beam focusing and beam deflection, and switchable beam focusing and beam splitting.