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.