Fine Tuning of Plasmonic Metal Array Structures for Effective Light Manipulation

Abstract

Improvements in light manipulation is the key for effective photoenergy conversions. Herein, we propose a method to improve the quality factor of metal nanostructure array using a relatively low temperature annealing. The method leads to the change in the extinction spectra of Au nanoprisms showing a narrow full width at half-maximum while maintaining structural anisotropy. X-ray diffraction and electrochemical measurements proved the improvement of the crystallinity of the Au nanoprisms as the origin of relatively high quality factor. Moreover, the method was also applied to the well-defined Au lattice structure prepared using electron-beam lithography, which resulted in a 5-fold improvement of the quality factors in the surface lattice resonance mode. We applied these structures to construct strong coupling systems with dye excitons. Ultra-strong coupling states was achieved by the optimization of the lattice modes to the energy of the excitons. The present systems could be applied to create controlled light-matter hybridized materials.