Terahertz-induced dielectric property enhancement in conjugated polymer-metal hybrid metamaterials

Metamaterials, artificial constructs renowned for their extraordinary electronic and optical properties, have garnered significant interest due to their potential in intelligent and biocompatible applications. This interest has driven the exploration of integrating flexible, functional materials with metamaterials. Conjugated polymers (CPs), widely utilized in optoelectronics and biomaterials, exhibit unexpected changes in their electro-optical properties when incorporated into metamaterial frameworks. To investigate the relationship between chemical structures and these altered properties, we developed an innovative class of terahertz-activated polymers featuring conjugated main- chains and phosphate groups with inherent polarizing capabilities. These polymers were integrated with split ring resonators (SRRs) to form polymer-metal hybrid metamaterials. Our findings reveal a significant enhancement in the dielectric properties of these polymers when exposed to terahertz waves, a response distinct from that of graphene despite their conjugation structural similarities. Comprehensive research and simulation elucidated the mechanism behind this enhancement, attributing it to the influence of the excited, powerful, near-field electric fields around the SRRs. These fields induce and align the dipoles of phosphate groups, thereby improving electro-optical performance. The spatial extent of this enhancement effect is confined within 0.5 µm of the SRRs. Our research clarifies the altered properties of flexible materials when integrated with metastructures, offering valuable insights for advancements in electronics, particularly in terahertz technology and metamaterials.