Third-order non-linear optical properties of tetra-n-propylammonium bis (4,5-dithiolato-1,3-dithiole-2-thione) nickel (III)

Tetra-n-propylammonium bis (4,5-dithiolato-1,3-dithiole-2-thione) nickel(III) was synthesized and its third-order optical non-linearity was characterized using Z-scan technique with 40 ps laser pulse at 1064 nm. The Z-scan curves have revealed that the complex exhibits a typical saturable absorption (β=−4.3±0.3×10−12 m/W) and a negative non-linear refraction (n2=−2.7±0.2×10−18 m2/W). The molecular second-order hyperpolarizability γ was calculated to be 1.5×10−30 esu. These relatively large non-linear optical properties of the complex may have much to do with its special π-electron structure.