The investigation of the optical properties of liquid Ga nanoparticles embe
dded in a dielectric matrix by means of spectroscopic ellipsometry is repor
ted. The particles, which have the shape of truncated spheres and a radius
which is varied in a controlled way between 5 and 16 nm, are grown by the e
vaporation-condensation technique. The results are discussed in terms of th
e current effective medium models and give new information on the distribut
ion of the particles in the matrix as well as on their optical properties.
A resonance peak due to the plasmon-polariton electron excitations in the p
articles is observed in the imaginary part of the effective dielectric func
tion of the layer. Its position shifts to higher photon energies and the ha
lf width of the resonance increases with the decrease of the particle size.
The dielectric function of the particles is parametrized using the Drude d
ispersion equation. The obtained electron damping parameter increases with
the decrease of the particle size in accordance with the predictions of the
size theories of the optical properties of small particles.