Reconfiguration of Resonance Characteristics for Terahertz U-Shape Metamaterial Using MEMS Mechanism

We present the design, simulation, fabrication, and characterization of an out-of-plane reconfiguration of terahertz (THz) U-shape metamaterial. The U-shape metamaterial is consisted of bilayer cantilevers with different coefficient of thermal expansion. The electromagnetic tunability of U-shape metamaterial is accomplished by using electrostatic actuation mechanism to provide higher tuning range at lower driving voltage. The bilayer cantilevers are actuated toward the substrate by gradually increasing the bias and, then, completely snapped down when the bias reached the critical pull-in voltage. Therefore, this device can control the resonant frequency actively. The experimental results indicate that the device possesses 0.51-THz tuning range with polarization dependence compared to dc bias of 0 and 12 V. Moreover, this device can be a THz switch when rotated to different angle with respect to the polarization of incident light. Hence, such adaptive metamaterial device offers significant potential in realizing the multifunctionality in optical filter, polarization controller, and optical switch applications.