Broadband Mechanically Tunable Metasurface Reflectivity Modulator in the Visible Spectrum

Reflectivity modulation is a critical feature for applicationsin telecommunications, 3D imaging and printing, advanced laser machining,or portable displays. Tunable metasurfaces have recently emerged asa promising implementation for miniaturized and high-performance tunableoptical components. Commonly, metasurface response tuning is achievedby electro-optical effects. In this work, we demonstrate reflectivitymodulation based on a nanostructured, mechanically tunable, metasurface,consisting of an amorphous silicon nanopillar array and a suspendedamorphous silicon membrane with integrated electrostatic actuators.With a membrane displacement of only 150 nm, we demonstrate reflectivitymodulation by Mie resonance enhanced absorption in the pillar array,leading to a reflectivity contrast ratio of 1:3 over the spectralrange from 400-530 nm. With fast, low-power electrostatic actuationand a broadband response in the visible spectrum, this mechanicallytunable metasurface reflectivity modulator could enable high framerate dynamic reflective displays.