Fig. 4

Electroactuation devices. a Schematic of voltage-controlled cantilever. Reproduced with permission from [96], copyright Springer Nature, 2014. b Illustration of electrothermal micro-origami. Reproduced with permission from [113], copyright John Wiley and Sons, 2020. c Diagram of omega-ring metamaterial arrays controlled by MEMS. Reproduced with permission from [114], copyright AIP Publishing, 2014. d The electrically actuated varifocal lens. Reproduced with permission from [115], copyright American Chemical Society, 2021. e Schematic of electrically-controlled digital metasurface. Reproduced with permission from [116], copyright Springer Nature, 2020. f Schematic illustration of NEMS-tuning metasurface. Reproduced with permission from [117], copyright American Chemical Society, 2021