Exploring the nonlinear optical properties of gold nanoparticle colloids capped with Gum Arabic: A study utilizing continuous wave laser and Z-scan technique

Gold nanoparticles (AuNPs) colloids were synthesized using Gum Arabic (GA) in distilled water to improve their properties for optical applications. The nonlinear optical properties (NLO) of Gum-Arabic coated gold nanoparticles (GA-AuNPs) colloids were explored through the Z-scan technique. The nonlinear refractive index (n(2)) and the nonlinear absorption coefficient (B-eff) were measured at a constant wavelength of 637 nm and different laser intensities (1.1-1.5 kW/cm(2)). GA-AuNPs were synthesized by the reduction technique in distilled water and stabilized by Gum Arabic with the help of NaOH at various reaction times and temperatures. The absorption spectra, shape, and size of GA-AuNPs colloids were evaluated using Ultra-high-resolution scanning electron microscopy (SEM) and ultraviolet-visible (UV-vis) spectrophotometer. The synthesized nanoparticles have a spherical shape with a mean size ranging from 7 to 16 nm. No considerable effect on the size of nanoparticles (NPs) when the reaction time varies for the same temperature, however, this effect is noticed when the temperature is raised to 80 C. As the intensity of the laser increases, the n2 and Beff indices were also increased. The results suggest that GA-AuNPs have strong nonlinear absorption and scattering coefficients, which make them promising candidates for various applications, including optical limiting.