Rapid additive manufacturing of all-carbon, all-dielectric metastructures

Metamaterials have been explored to achieve extraordinary response to incident radiations, not accessible to conventional materials. Metamaterial attributes are derived from spatially arranged sub-wavelength resolved metaelements. Additive manufacturing technologies offer capabilities to fabricate complex metastructures with novel remarkable responses. Two-photon polymerization (TPP) based additive manufacturing has gained popularity due to its exceptional precision and minimal processing stages. However, the major bottleneck in the development of TPP based fabrication is its dependence on engineered/proprietary/expensive two-photon active materials for initiation of polymerization process. Here, we propose an acrylate and carbon dot composite resin for additive manufacturing of all-carbon, all-dielectric metamaterials. Two-photon irradiation induces photoinduced electron transfer from the surface states of carbon quantum dots, which in turn initiates the TPP. The composite resin is devoid of any other two-photon dye/initiator. The effect of carbon dot concentration on fabrication process parameters and fabrication resolution have been systematically investigated. Several linear/ complex planar and 3D structures have been fabricated with high replication fidelity. As a proof-of-concept, the composite resinhas been used for the realization of resonant and chiral metamaterials. Furthermore, theoretical calculations are also performed to evaluate the optical activity of these metastructures. Our results demonstrate steps towards realizing all-dielectric, all-carbon based metamaterials.