Tunable Structural Color in Au-Based One-Dimensional Hyperbolic Metamaterials

Structural coloration arising from nanoscale light-matter interactions has emerged as a key research area in nanophotonics. Among the various materials investigated, noble metals-particularly gold-play a central role due to their well-defined plasmonic response and chemical stability, but their structural coloring typically requires complex and highly engineered nanostructures. However, modern photonic technologies demand scalable approaches to produce structural colors that can be finely tuned. In this contribution, we experimentally and numerically demonstrate the fine tunability of structural color in gold-based one-dimensional hyperbolic metamaterials (1D-HMMs) by varying their structural parameters: number of layers (<i>N</i>), period (<i>T</i>), and filling fraction (<i>p</i>). Our results show that variations in <i>N</i> lead to changes in luminance with minimal shifts in chromaticity, while variations in <i>T</i> introduce moderate color shifts without affecting luminance. In contrast, changes in <i>p</i> produce the largest modifications in chromaticity, though the trend is non-monotonic and less predictable. These findings highlight the potential of 1D-HMMs for achieving finely controlled gold-based coloration for advanced photonic technologies.