Degenerate four-wave mixing determination of third-order optical nonlinearities of three mixed ligand nickel(II) complexes

Three mixed ligand nickel(II) complexes were synthesized and characterized by UV–visible, IR, MS and elemental analysis. Their off-resonant third-order nonlinear optical properties were measured using femtosecond laser and degenerate four-wave mixing technique. The third-order nonlinear optical susceptibilities χ(3) were 3.20–3.51 × 10−13 esu. The nonlinear refractive indexes n2 were 5.89–6.45 × 10−12 esu. The second-order hyperpolarizabilities γ of the molecules were 3.20–3.50 × 10−31 esu. The response times were 55–81 fs. The results show that these complexes have potential nonlinear optical applications.