On the optimal plasmonic resonances in gold nanospheres embedded in dispersive media

New fundamental upper bounds have recently been given regarding the optimal plasmonic multipole resonances of a rotationally invariant sphere embedded in a lossy surrounding medium. The new theory is based on a generalized optical theorem for the absorption of a sphere in a lossy medium and employs straightforward analysis to explicitly maximize a concave function. The new bounds are briefly summarized in this paper and then employed in a study concerning the effectiveness of using gold nanospheres as absorbers of the sizes typically used in biomedical applications and plasmonic photothermal therapy.