The refractive index (RI) sensor is utilized in various applications in industry because of its recognizing physical and biological parameters. The fiber optic RI sensor is perfect for RI measurement of fluids in industrial, chemical and food processing industry applications. Nanoparticles (Nps) of noble metals have turned out to be exceptionally fascinating materials as result pf their distinct properties. The fabrication of metallic nanoparticles (NPs), mostly gold and silver, has attracted much interest due to their surface plasmon effect related properties those are potentially useful for biological applications. Controling size, shape, and surface functionalization are very important issues in Au NP synthesis. Due to their chemical stability and prominent optical properties, gold nanoparticles (Au-NPs) were extremely used in Nano-medicine. Morphological characteristics of formed NPs can be controlled by laser fluence, spot size, wavelength, pulse width, and repetition rate of laser pulse.