Effect of aluminum nanoparticles on the linear and nonlinear optical properties of PVA

Linear and nonlinear optical properties of Polyvinyl Alcohol thin film doped with aluminum nanoparticles have been investigated experimentally. Aluminum nanoparticles were produced using pulsed laser ablation method. The fundamental wavelength of Nd-YAG laser at 7 ns pulse width was employed to produce aluminum nanoparticles in water at different sizes and concentrations. TEM images were used to study the nanoparticles after ablation. UV-Vis-NIR spectroscopy data were used to extract the real and imaginary parts of refractive index and dielectric functions of films and z-scan technique was used to measure the nonlinear refractive index and absorption coefficient of films. Results show that in comparison with particle size, the concentration of doped nanoparticles is more effective on the optical properties of polymers thin films. Band gap energy of polymer films was decreased with decreasing the size and increasing the concentration of nanoparticles while their refractive index was decreased.