Surface Plasmon Resonance in Metal Nanoshells with air-core: Computational Study Using DDA

Metal nanoshell interiors filled with air have wide applications because of their tunable properties from visible to near-infrared regions of the electromagnetic spectrum. Their sensitive response to environmental changes makes them useful for sensing applications. We investigated the effect of shell material, shell thickness, surrounding medium, and size effect on the extinction spectra of nanoshells using a dipole as well as a numerical model (discrete dipole approximation). Nanoshell geometry reduces the material cost and gives the extra degree of freedom to control the plasmon dipole resonance. A comparative analysis between metallic nanoshells and solid nanospheres indicates that hollow nanostructures exhibit sensitivity to environmental variations. Investigations into the influence of shell thickness on the extinction spectrum of metallic nanoshells reveal a blue shift in the peak position as the shell becomes thicker. Additionally, the normalized electric field distribution around the metallic nanoshells intensifies with an increase in the refractive index of the surrounding medium.