Enhanced third-order optical susceptibility in Ag-doped CeO2 nanostructures under pulsed Nd-YVO4 laser

Abstract

In this research, cerium dioxide nanoparticles with different Ag doping levels were prepared through a one-pot hydrothermal synthesis route. The as-prepared samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM). The linear optical characteristics were analyzed by photoluminescence (PL) emission technique at an excitation wavelength of 250 nm. A red shift towards longer wavelengths was detected in NBE-related energies of Ag-doped samples as compared to Un-doped CeO2 NPs. The incorporation of Ag in CeO2 lattice was also justified using fluorescence quenching. The third-order nonlinear optical parameters were investigated using single-beam Z-scan technique under a 1064 nm Nd-YVO4 laser beam with 50 ns pulse width and 10 KHz repetition rate as an excitation source. All samples presented negligible nonlinear absorptions and self-defocusing responses due to negative lens effects in the near infra-red region. The Z-scan results indicated stronger third-order nonlinear susceptibilities for Ag-doped CeO2 samples as compared to Un-doped NPs. The highest third-order nonlinear susceptibility was found to be about 22.19×10-6esu belonging to 0.75Ag-doped CeO2 sample with an enhancement about 4.5 times higher than that of Un-doped CeO2.