Third-order optical nonlinearities of an organometallic complex: Bis(tetra-n-propylammonium)bis(2-thioxo-1,3-dithiole-4,5-dithiolato)cuprate(II) doped in solid PMMA films

An organometallic complex, bis(tetra-n-propylammonium)bis(2-thioxo-1,3-dithiole-4,5-dithiolato)cuprate(II), [(C3H7)4N]2[Cu(dmit)2] (dmit2−=4,5-dithiolate-1,3-dithiole-2-thione), abbreviated as PrCu, was synthesized. The films of PrCu were prepared using spin coating method. The third-order nonlinear optical properties of PrCu in acetone solution and PMMA films were investigated by Z-scan technique at 1064 nm with laser duration of 20 ps. The Z-scan spectra reveal that the composite films exhibit large negative nonlinear refractive indices of the order of 10−15 m2/W, which are three orders larger than that in acetone solution. The nonlinear absorption coefficients were calculated to be 9.416×10−10 m/W. For the composite films, the figure of merit, W and T, meet the requirement of all-optical switching devices. The experimental results show that the PrCu-doped PMMA films have potential applications for nonlinear optical devices.