Vertically-Aligned Hybrid Plasmonic Nanoantennas with Tailored Visible-Light Responses.

Plasmonic nanoantennas enable unprecedented control of light-matter interactions at subwavelength scales, yet conventional fabrication methods limit designs to planar geometries with fixed resonant properties. Here, we demonstrate 3D-printed plasmonic nanoantenna arrays featuring record aspect ratios (15:1), miniaturized features (∼40 nm), and high density (1.0 × 106 mm-2) on silicon wafers. Our approach enables the single-step fabrication of vertically standing multimaterial nanoantennas with unified dimensional control, thereby overcoming challenges in 3D plasmonic integration. By engineering material composition and layer arrangement in hybrid architectures, one can tune localized surface plasmon resonances across the visible spectrum, while polarization-selective responses enable multifunctional operation. These 3D-printed nanoantennas eliminate parasitic substrate losses inherent to planar designs and exhibit broadband operation through complementary plasmonic modes. The combined capabilities of high-density integration, spectral tunability, and out-of-plane control position this platform as a practical tool in photodetection, solar-energy devices, and on-chip nanophotonics.