  Metallic nanoparticles embedded in dielectrics permit enhanced capture of
light at specific wavelengths through excitation of plasmons, i.e. the quanta
of coherent and collective oscillations of large concentrations of nearly free
electrons. In order to maximize the potential of such enhanced absorption in
useful tasks, such as the generation of carriers in photocatalysts and
semiconductors, it is important to be able to predict and design plasmonic
nanocomposites with desired wavelength-dependent optical absorption. Recently,
a mixing approach formulated by Garcia and co-workers [Phys. Rev. B, 75, 045439
(2007)] has been successfully applied to model the experimentally measured
broadband optical absorption for ternary nanocomposites containing alloys or
mixtures of two metals (from Ag, Au or Cu) in SiO dielectric. In this work we
present the broadband optical behavior of important optical coating dielectrics
(SiN and SiO) and photocatalyst (TiO) containing various configuration of
nanoparticles of Al, Au, Ag, or Cu. The spectral behavior of various
combinations of the metallic species in the dielectrics was optimized to show
either broadband solar absorption or strong multiple plasmonic absorption
peaks. The applications of such nanocomposite materials in solar energy
harvesting and spectral sensing are also presented and discussed.
