Mechanical and Optical Properties of Nanocluster‐Silica Metamaterials

ABSTRACT Nanostructured metamaterials with complex 3D geometries can be fabricated using two‐photon lithography but are typically limited to specific materials by the available photoresists. Here, we develop a two‐photon lithography photoresist for fabricating mechanically robust and optically active metamaterials. This photoresist consists of silver nanocluster photointiators in a polyhedral oligomeric silsequioxane (POSS) polymer matrix. Printed nanocomposites show a 216% increase in elastic modulus and 166% increase in energy absorption compared to structures made of POSS, while retaining 96% elastic recovery. Nanocomposite gyroid nanolattices reach 80% strain at failure. The nanolattice energy absorption is among the highest for lightweight nanoporous materials. Thermal annealing is used to convert the printed nanocomposites to nanoparticle‐embedded glass with 54% higher energy absorption than fused silica. The annealed gyroid nanolattices contain silver nanoparticles and exhibit plasmonic activity. Right and left‐handed chiral nanolattices result in different transmission spectra under linearly polarized light.