Magnesium metallic nanoparticles have been synthesized using the pulsed laser ablation in liquid media technique (PLAL) in the range of 20–30 nm by varying the laser ablation time. During the laser ablation process, the laser-induced breakdown spectroscopy (LIBS) technique is used to investigate the physicochemical properties as laser-induced Mg plasma in terms of spectral line intensities and their plasma parameters ( n e and T e ). The X-ray diffraction technique and UV-visible technique show that the produced samples have a crystalline structure, and as the laser ablation time increases, the value of the absorption peak shifts to lower wavelengths and the average particle decreases, respectively. The use of the PLAL technique shows the capability to produce a metallic structure based on purging the solution by molecular nitrogen. The use of the LIBS technique shows a good and fast tool for detecting their particle sizes and the differentiation between the metallic form and its oxide structure.

Alumina nanoparticles with different average particle sizes were synthesized by pulsed laser ablation of Al plates in ethanol, followed by laser irradiation at different times. Their optical and structural properties were investigated by different techniques. The experimental work showed that as the time of post-laser irradiation increased, the average particles’ size of alumina decreased. The decrease in the particle size is detected by using x-ray diffraction (XRD) technique and UV-visible absorption spectroscopy technique (UV–VIS) and characterized by laser-induced breakdown spectroscopy (LIBS). The LIBS technique was utilized as a diagnostic tool with XRD and UV–VIS for determining the nanoparticles’ size. Laser-induced plasma parameters such as electron density and electron temperature were determined. A relationship has been established between the electron temperature and the nanoparticles’ size. The results reflect the significance of correcting the spectral intensity of the emitted line for the effect of self-absorption in the LIBS experiment.