Formation of Highly Tunable Periodic Plasmonic Structures on Gold Films Using Direct Laser Writing

TL;DR

This paper demonstrates a direct laser writing technique to create highly tunable periodic gold nanostructures with controllable plasmonic resonances, enabling advanced applications in sensing and photonic devices.

Contribution

It introduces a method for fabricating shape-controlled gold nanostructures with tunable resonances using direct laser writing on different film thicknesses.

Findings

Resonance peaks depend on nanostructure shape and morphology.

Resonance position can be modulated by laser pulse energy and grating period.

The method enables precise control of plasmonic properties for sensing applications.

Abstract

Direct laser writing method is a promising technique for the large-scale and cost-effective fabrication of periodic nanostructure arrays exciting hybrid lattice plasmons. This type of electromagnetic mode manifests a narrow and deep resonance peak with a high dispersion whose precise controllability is crucial for practical applications in photonic devices. Here, the formation of differently shaped gold nanostructures using the direct laser writing method on Au layers of different thicknesses is presented. The resonance peak is demonstrated to be highly dependent on the shape of the structures in the array, thus its position in the spectra, as well as the quality, can be additionally modulated by changing the morphology. The shape of the structure and the resonance itself pertain not only on the laser pulse energy but also on the grating period. This overlapping effect occurring at distances smaller than the diameter of the focused laser beam is studied in detail. By taking advantage of the highly controllable plasmonic resonance, the fabricated gratings open up new opportunities for applications in sensing.