The Third-Order Nonlinear Optical Properties in Cobalt-Doped ZnO Films

Abstract

We quantitatively investigate the third-order optical nonlinear response of Co-doped ZnO thin films prepared by magnetron sputtering using the Z-scan method. The two-photon absorption and optical Kerr effect are revealed to contribute to the third-order nonlinear response of the Co-doped ZnO films. The nonlinear absorption coefficient 𝛽 is determined to be approximately 8.8 × 10 −5 cm/W and the third-order nonlinear susceptibility 𝜒 (3) is 2.93 × 10 −6 esu. The defect-associated energy levels within the band gap are suggested to be responsible for the enhanced nonlinear response observed in Co-doped ZnO films.

Dependence of Nonlinear Optical Response of Anatase TiO 2 on Shape and Excitation Intensity

“…We contribute it to the effect of the well-defined structure of NWAs, which possess lower lattice defects, surface defects and residual stress after annealing. [35,37] It could be noticed that, with the increase of the incident intensity, 𝛽 of all the three samples gradually tends to be equal. As the incident intensity becomes higher, 𝛽 becomes smaller.…”