Green Synthesis of Noble Metal Nanoparticles: Nonlinear Optics and Applications

This study presents a green method for synthesizing gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) employing Gum Arabic extract as a reducing and stabilizing agent. The synthesized nanoparticles are characterized using UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). The visible color change and the presence of surface plasmon resonance (SPR) peaks confirmed the formation of silver and gold nanoparticles. The size of the nanoparticles was determined from the UV-Vis spectra data, and the results were compared to sizes measured by TEM. The nonlinear refraction (n2) and nonlinear absorption (β) coefficient of AgNPs and AuNPs at 488 and 514 nm were investigated under continuous wave mode excitation using the Z-scan technique. By fitting the experimental data to the Z-scan theoretical equations, the nonlinear refraction index and the nonlinear absorption coefficient were found. The origin of the nonlinearities was discussed, and it was proposed to be of thermal effect for the nonlinear refractive index and reverse saturation absorption for nonlinear absorption. Optical limiting and switching were demonstrated by taking advantage of the samples’ nonlinear optical characteristics. Received: 22 July 2024 | Revised: 25 September 2024 | Accepted: 26 November 2024 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data are available from the corresponding author upon reasonable request. Author Contribution Statement Fryad Z. Henari: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization, Supervision, Project administration. G. Roshan Deen: Conceptualization, Software, Formal analysis, Resources, Data curation, Visualization.