Reconfigurable Metamirrors Based on Compliant Mechanisms

Highly-robust reconfigurable metadevices that offer a viable means for the precise control of electromagnetic waves are of immense practical importance for information, sensing, and communication technologies. A variety of approaches, including introducing active materials and tunable components such as varactor diodes into meta-atoms, have been developed to enable reconfigurable metamaterials that operate at microwave frequencies. However, complex fabrications involving multiple materials, sophisticated wiring, multilayer aligned photolithography, etc., are generally required to facilitate the tunability. Given that metamaterials derive their electromagnetic properties from engineered subwavelength building blocks, altering meta-atom shapes is a powerful means of regulating metamaterial responses. In this work, by exploiting an electromagnetic/mechanics co-design approach, a highly-robust chiral metamirror enabling electromagnetic wave polarization switching based on compliant mechanisms is demonstrated. Reconfigurable spin-selective reflection and circular dichroism are experimentally observed. More importantly, a robustness test shows that the investigated meta-atom can withstand more than 10 000 reconfigurations without structural damage and mechanical resistance fluctuation, indicating long-term operational reliability of the metadevice. The results suggest a new paradigm for achieving reliable, low-cost reconfigurable metadevices that leverage a combination of compliant mechanisms and electromagnetic metamaterials for practical applications, especially when operation in harsh or challenging environments is required.