NEMS-based asymmetric split ring resonators for thermomechanically tunable infrared metamaterials

This paper presents a nanoelectromechanical systems (NEMS)-based tunable infrared (IR) metamaterial formed with an array of Au/Si bilayer split ring resonators (SRRs) having two asymmetric arms. The wider arm of the SRR is anchored on the device substrate, while the thinner arm is suspended above the substrate and can be thermally actuated to bend downward. The thermomechanical deflection of the nanocantilever-like thin arm changes the air gap between the two arms, thus modulating the optical resonance modes of the SRR. This tunable metamaterial is rather easy to manufacture and provides more than 90% optical signal modulation at the mid-IR wavelength of 3.6 μm.