Characterization Of Nonlinear Optical Properties Of Silver Nanoparticles At Differently Concentrated Particle Sizes

The study of nonlinear properties of Silver Nanoparticles (Ag NPs) has increased recently due to its application in all optical switching devices. In this study, the third-order nonlinear optical properties of (Ag NPs) are investigated further with different particle sizes and concentrations. Particles with sizes 10 nm and 20 nm in polyvinyl alcohol (PVA) solution were studied using a Z-scan technique at 980 nm wavelength. Moreover, three different concentrations are investigated particularly 3 mg, 4 mg and 5 mg in the same solution and using the same technique. The values of the nonlinear refractive index (n₂) and the nonlinear absorption coefficient (β) were measured and compared according to practical size and concentration of nanoparticles. The nonlinear refractive index (n₂) show a negative value for each sample, which act as a divergent lens, due to thermal self-defocusing effect and reverse saturable absorber was observed in Nano solutions due to two-photon absorption process. As a result, the application of these Nano solutions for optical switching devices was investigated by calculate the two figures of merit W and T. Any increase in concentration of Ag NPs makes the solution closer to the suitability condition (W > > 1 and T < 1). The Only solution at 20 nm particle size with 5 mg concentration of Ag NPs will satisfy the condition of suitability at W = 2.66 and T = 0.94 for all optical switching applications.