Abstract:
In this paper we compare the optical absorption for
nanospheres made from a range of transition and alkali metals
from Li (A=3) to Au (A=79). Numerical solutions to Mie theory
were used to calculate the absorption efficiency, Qabs, for
nanospheres varying in radii between 5 nm and 100 nm in
vacuum. We show that, although gold is the most commonly used
nanoparticle material, its absorption efficiency at the plasmon
resonance is not as strong as materials such as the alkali metals.
Of all the materials tried, potassium spheres with a radius of 21
nm have an optimum absorption efficiency of 14.7. In addition
we also show that, unlike gold, the wavelength of the plasmon
peak in other materials is sensitive to the sphere radius. In
potassium the peak position shifts by 100 nm for spheres ranging
from 5 nm to 65 nm, the shift is less than 10 nm for gold spheres.
