Tuning of the surface plasmon resonance of aluminum nanoshell near-infrared regimes

The natural abundance of aluminum is far better than those of noble metals like silver and gold. Its plasmonic properties have not been explored in detail, as they generally lie in the ultraviolet region of the electromagnetic (EM) spectrum. Nevertheless, recent advanced research work in the literature predicts aluminum to be the next and best plasmonic material suitable for exciting cost-effective applications. Inspired by this, we have analyzed the optical properties of aluminum metal nanoshells using semi-analytical and numerical finite difference time domain models. In the semi-analytical model, we have discussed an electrostatic approach for nanoshell geometry and derived the exact Frolich condition and corresponding plasmon resonance peak position. These plasmonic peaks and their tunability in different regimes of the electromagnetic spectrum via the shell thickness are the main thrust of this work. For proof of concept, we have compared simulated and modeled results in different parameter domains and observed that both sets of results are in agreement with each other. We have also visualized the distribution of the electric field intensity near the aluminum nanoshell surface under SPR conditions, which covers a broad range of applications.