Multi-Scale Engineering of Photonic Meta-Structures With Emergent Optical Resonances via Colloidal Crystal...

Metasurfaces offer control over light-matter interactions, but their material scope is often constrained by top-down fabrication techniques, limiting compositional flexibility in meta-atoms and the accessible optical properties. Herein, a bottom-up approach integrates colloidal crystal engineering with DNA with lithographically defined microwell templates to create meta-structures composed of nanoparticle superlattices that function as programmable meta-atoms. The microwell environment stabilizes non-equilibrium superlattice habits inaccessible with homogeneous crystallization, decoupling habit formation from lattice symmetry. This approach enables tuning of optical response through hierarchical parameters: 1) nanoparticle composition and size, DNA length, and lattice symmetry define superlattice optical characteristics; 2) superlattice size and habit determine resonator supported modes; and 3) inter-superlattice spacing and arrangement govern collective lattice effects. This multiscale modularity enables access to a vast combinatorial design space for optical engineering. As proof-of-concept, a meta-structure comprised of periodic cylindrical superlattices exhibiting a near-infrared Mie- resonance is fabricated. Despite being composed of metallic gold nanoparticles, the superlattices exhibit an emergent dielectric-like response with low effective extinction in the NIR/mid-IR regime, enabling volumetric electromagnetic field penetration. Field maps show resonant behavior characteristic of magnetic dipole Mie modes. By integrating colloidal assembly with system-level optical functionality, this work establishes a bottom-up framework for designing photonic meta-structures.