In recent years there has been a renewed interest in research into plasmonic metamaterials. This includes new approaches in designing metamaterials that display hyperbolic dispersions and new fabrication techniques which take advantage of the control and uniformity possible with self-assembled, template based fabrication, and which significantly benefit from both low cost and high throughput. These approaches can readily achieve the dimensions required for the development of metamaterials in the visible and near-infra-red spectral ranges where considerable research has already been carried out. Currently, research in the near-UV to deep-UV (DUV) spectral regions (3-6 eV) is attracting increasing excitement due to the huge number of potential applications, including fluorescence enhancement, surface enhanced resonant Raman scattering, high sensitivity bio-sensing and nanoscale photolithography. Here we describe a self-assembled approach for the fabrication of metamaterials based on aluminium nanowires for applications spanning the deep to near-UV spectral range. Optical characterisation of such highly anisotropic UV metamaterials show the resonances which are tunable throughout the deep UV spectrum (200-500 nm) and which exhibit hyperbolic dispersion from the NUV to infra-red frequency range.
|