Tunable plasmonic resonance by photothermal deformation in Ag-SiO₂ semi-shell nanostructures and enlargement of the controllable spectral region by UV-curable resin

The Ag semi-shell, a nanostructure comprising a dielectric nanosphere partially covered with Ag metal, can have its metallic shell deformed through a melting process under the illumination of plasmonic resonance. We have investigated the photothermal deformation process in Ag semi-shells and observed intensity-dependent melting deformation of the shell and a corresponding blueshift of the resonance peak. This indicates that the plasmonic resonance of the Ag semi-shells can be continuously controlled through laser irradiation. Furthermore, when the Ag semi-shells were coated with a UV-curable resin, the initial resonance peak wavelength was red-shifted, and the controllable spectral region was increased by a factor of two compared to that without the UV-curable resin. This large continuous control of the optical response through melting deformation of the shell has potential applications in optical memory, plasmonic color, and other areas.