Transient nonlinear optical response of novel neutral unsymmetrical nickel dithiolene complexes

The transient nonlinear optical response of five novel unsymmetrical neutral nickel dithiolene complexes has been studied experimentally in the nanosecond regime at 532 and 1064 nm using the Z-scan technique. The nonlinear absorption and refraction parameters β and γ′ respectively, the third order susceptibility χ(3) of the solutions and the effective second-order hyperpolarizability γ of the complexes were determined at both wavelengths. All dithiolene complexes studied were found to exhibit significant nonlinear refraction, larger than the corresponding nonlinear absorption. The second-order hyperpolarizabilities γ values were found to be as large as 10−27 esu. The origins of the observed nonlinear optical response are also discussed.