Nanoporous gold nanoleaf as tunable metamaterial

We have studied optical properties of single-layer and multi-fold nanoporous gold leaf (NPGL) metamaterials and observed highly unusual transmission spectra composed of two well-resolved peaks. We explain this phenomenon in terms of a surface plasmon absorption band positioned on the top of a broader transmission band, the latter being characteristic of both homogeneous solid and inhomogeneous diluted Au films. The transmission spectra of NPGL metamaterials were shown to be controlled by external dielectric environments, e.g. water and applied voltage in an electrochemical cell. This paves the road to numerous functionalities of the studied tunable and active metamaterials, including control of spontaneous emission, energy transfer and many others.

Automated summary

The optical properties of single-layer and multi-fold nanoporous gold leaf (NPGL) metamaterials exhibit highly unusual transmission spectra with two distinct peaks. This phenomenon is explained by the presence of a surface plasmon absorption band on top of a broader transmission band, which is characteristic of both homogeneous solid and inhomogeneous diluted Au films. Additionally, the transmission spectra of NPGL metamaterials can be manipulated by external dielectric environments such as water and applied voltage in an electrochemical cell, suggesting potential applications in controlling spontaneous emission and energy transfer.