Periodic Array of Subwavelength MEMS Cantilevers for Dynamic Manipulation of Terahertz Waves

We experimentally demonstrate the active manipulation of terahertz (THz) waves using a periodic array of electrostatically actuated subwavelength microelectromechanical system cantilevers, which effectively behave like a metamaterial. The design methodology for achieving desired ON- and OFF-state resonance frequencies through electromechanical optimization is presented. The microcantilever metamaterial has a switching range of 0.29 THz and a modulation depth of 60% at 0.59 THz. Utilizing metal layer thickness to optimize the devices, an improvement of 40% is achieved in switching range. The microcantilever metamaterials are highly miniaturized, extremely scalable, and electrically controlled with attractive electro-optic performance. Multiple cantilevers can be placed in a desired fashion to form complex unit cell geometry to realize advanced THz manipulation, such as polarization switching, bandwidth tunable filters, multicolor imagers, and so on.