Electroactive Tuning of Double‐Layered Metamaterials Based on π‐Conjugated Polymer Actuators

Abstract

Novel electroactive metamaterials working in the terahertz (THz) and microwave frequency ranges are demonstrated utilizing π‐conjugated polymer actuators. Metamaterials are artificial composite materials based on subwavelength resonant elements called “meta‐atoms.” The resonant character of meta‐atoms typically restricts their operating frequency to a narrow range, therefore it is crucial to make them tunable in order to develop practical devices. A promising tuning scheme is based on changing the mutual position of meta‐atoms in a composite. When two meta‐atoms are placed in close vicinity such that their near‐fields interact, their resonant characteristics can be tuned by altering their relative position and/or orientation. Here linear actuators made from heavily doped polypyrrole films are utilized to change the relative lateral position of two THz metasurfaces, and accordion‐shaped origami actuators are used to change the distance between two microwave meta‐atoms. In both cases significant tunability of the resonances is obtained by the application of a control voltage. This approach here may open a new direction for creating tunable metamaterials based on a rich variety of π‐conjugated polymer actuators.