Nonlinear Optical Properties of Core@Shell Nanoparticles of Gold and Moringa Oleifera Leaves via Laser Ablation Technique

In this paper, gold and Moringa oleifera leaf nanoparticles were synthesized using laser ablation techniques by Nd-YAG laser with a wavelength of 1064 nm, energy of 100 mJ, and a frequency of 3 Hz. The gold plate and Moringa oleifera leaf tablets (after grinding it then being compressed and exposed to heat) were immersed in 5 ml of distilled water for each one individually to synthesize nanoparticles as a first step. The second step was a synthesis of core@shell from gold and Moringa nanoparticles with different pulse numbers (250,500, and 750) pulse where gold was used as the core and Moringa as the shell and vice versa. The prepared samples were characterized using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The Z-Scan technique with a closed aperture system was used to study the nonlinear optical properties of the prepared samples. The results show the success of the techniques used where the particle size was between (15–50) nm. The nonlinear properties of the prepared samples showed that they have a negative nonlinear refractive index, that is, the nonlinear transmittance curve begins with a peak and is followed by a trough.