Selective control of the optical properties of thin film layers is necessary in various domains such as photovoltaics and optoelectronics. Through localized surface plasmon resonance, silver nanoparticles exhibit selective optical properties in the visible wavelength range depending on their size and shape. The tremendous progress in nanoparticle synthesis methods, leads to easy fabrication of nanoparticles of various sizes and shapes. By embedding various nanoparticles in a thin film layer, the optical properties are engineered. Silver nanospheres and nanocubes are synthetized by a modified polyol process and randomly deposited in a non-absorbing polymer host matrix. Spectroscopic ellipsometry characterizations determine the complex optical indices of single shape nanoparticles, two shaped nanoparticles and multilayer configuration thin film layers. The spectroscopic ellipsometry data are fitted by a Cauchy law, accounting for the optical properties of the polymer host matrix, and one or several Gauss laws, accounting for the optical properties of the nanoparticles. The extinction coefficient of the blend and multilayer layers show a simple superposition of the extinction coefficients. Therefore, the nanoparticles do not interact in the thin film layers.