Striking gold: study explores light resonance with layered metallic arrays
Striking gold: study explores light resonance with layered metallic arrays lead image
When reduced to the nanometer scale, gold and silver can help manipulate light, which makes them popular materials for an array of medical applications including disease detection. In nanostructured form, the metals can act as optical amplifiers whose operation can be tuned by modifying their sizes and shapes. With single gold nanostructures, localized surface plasmons – oscillations of a metal’s electrons caused by light – account for the useful optical properties.
Still, the degree of control over light using gold nanostructures can be greatly improved, and the use of two-nanoparticle assemblies, which can further amplify the light that reaches them, is gaining attention.
Researcher Edgar Briones examined how such light changes as a function of the separation of two gold nanostructures in a sandwich-like configuration, as well as with the sizes of the nanostructures themselves.
“From this research, we show how strong the interaction of these particles is,” said Briones. “In addition, we show that the effects can be observed with the naked eye, since it has an impact on the coloration of the nanostructures,” said Briones.
Using a COMSOL Multiphysics software package, Briones built a simple numerical model to analyze the light reflectance and absorbance spectra of the layered nanostructure arrays and evaluate their resonance properties.
The study showed how manipulating the size of the arrayed layers can shift resonance from the near infrared band to the visible band. Also, it yielded a broader gamut of color spectrum, including shades of magenta, orange, yellow and red, compared to single-layered nanostructures.
The results suggest how arrayed nanostructures can be used to overcome current limitations and open new possibilities for their utility.
Source: “Improving the color gamut of gold nanostructures using vertical tandem nano-disks,” by Edgar Briones, AIP Advances (2024). The article can be accessed at https://doi.org/10.1063/5.0231859 .
