Optical Nonlinearity of Ag/PVP Thin Films: Particle Size Dependence of χ(3)

Silver (Ag) nanoparticles were prepared in Poly Vinyl Pyrrolidone (PVP) by laser ablation with 1064 nm and 532 nm wavelengths. Particles were characterized by using an electron microscope. The mean diameter of particles is found to be decrease with decrease in ablation wavelength. Third order nonlinearities of Ag/PVP nanocomposite films were studied by Z‐scan technique with 7 ns Nd: YAG laser pulses at 532 nm. Third order susceptibility (χ(3)) is measured with an emphasis on particle size dependence. Open aperture Z scan measurement indicated that composite films exhibited reverse saturable absorption.