Nonlinear Optical Studies of (C₄H₉)₄NNi(dmit)₂ by Z-Scan Technique

Nonlinear optical properties of an organo-metallic compound (C₄H₉)₄NNi(dmit)₂ (dmit=2−thioxo-1,3-dithiole-4,5-dithiolate), abbreviated as BuNi, dissolved in acetone, are investigated using the Z-scan technique with a 40 ps pulse width at 1064 nm and a 1 ns and 15 ns pulse width at 1053 nm. Strong saturable absorption is found when the sample solution is irradiated by 40 ps and 1 ns laser pulses. When irradiated with a 15 ns laser pulse, a stronger reverse saturable absorption is found. The nonlinear optical absorption coefficients are -1.06×10^-11, −2.02×10^-11 and 2.73×10⁻¹⁰ m/W, respectively. All the results suggest that BuNi may be a promising candidate in the application of laser pulse compression in the near-infrared waveband.