Tunable metasurfaces

Tuning the optical response of metasurfaces can unleash their full potential as compact and reactive optical elements. Here, we present two different approaches to tune the spectral response of a metasurface. In the first approach, a micro-electromechanical system(MEMS)-actuated metasurface is demonstrated in the visible range of the optical spectrum. It consists of an amorphous silicon nanopillar array and a suspended silicon membrane with integrated electrostatic actuators. The second approach utilizes light itself to reconfigure the metasurface by trapping nanoparticles within a templated plasmonic substrate. Optical forces control the position of the nanoparticles, which in turn tune the metasurface spectral response.