Enhanced 2PA nonlinear absorption and optical limiting behavior of pure, unitary- and binary-doped CuO nanoparticles underneath laser excitation

Pure, unitary (Zn and Bi), and binary-doped (Zn/Bi) CuO nanoparticles were synthesized using Moringa oleifera leaf extract. XRD analysis confirmed the monoclinic phase, and the incorporation of Zn[Formula: see text] and Bi[Formula: see text] into Cu[Formula: see text] ions was observed. FT-IR spectra provided molecular vibration data, while FE-SEM revealed various nanostructures (spherical, nanorods, rice-shaped, and nanoplates). EDAX analysis showed the elemental compositions of Cu, O, Zn, and Bi. Zeta potential measurements indicated negative charges of −34.23[Formula: see text]mV, −33.86[Formula: see text]mV, −32.6[Formula: see text]mV, and −32.0[Formula: see text]mV for pure, Zn-doped, Bi-doped, and Zn/Bi-doped CuO nanoparticles. UV–Vis spectra revealed a robust absorption peak in the 256–276[Formula: see text]nm range, and the optical bandgap was determined. PL spectra indicated peak intensity growth due to oxygen defects. Nonlinear optical properties were studied using the [Formula: see text]-scan technique, and Bi-doped CuO exhibited superior nonlinear absorption and optical limiting behavior, making it a promising candidate for laser damage protection.