Third-order Nonlinear Optical Properties of An Organo-metallic Complex

The 2-thioxo-1,3-dithiole-4,5-dithiolato (dmit) complexes exhibits very large and fast third-order NLO response and may be promising candidates for the applications in the field of nonlinear optics. An organometallic complex, ethyltriphenylphosphonium bis(2-thioxo-1,3-dithiole-4,5-dithiolato)aurate(III) (abbreviated as TPEtAu) is synthesized and the third-order nonlinear optical properties of TPEtAu dissolved in acetonitrile are investigated by Z-scan technique with 20 ps pulse width at 1064 nm and 532 nm, respectively. The TPEtAu sample solution exhibits strong self-defocusing effect both at 1064 nm and 532 nm, the negative nonlinear refraction coefficients n(2) are estimated to be as high as -8.48x10(-12) esu and -8.26x10(-12) esu, respectively. In additon, a reverse saturable absorption has been found only at 532 nm and the absorption coefficient beta is 1.88x10(-11) m/W. All the results suggest that TPEtAu has potential for the application of all-optical switching.