Study of third-order nonlinear optical and all-optical switching properties of palladium metal–organic complex

We report the results of studies on third-order nonlinear optical properties of a newly synthesized palladium metal–organic complex [PdLPPh3] (L = N-(2-pyridyl)-N′-(5-chlorosalicylidene)hydrazine) both in film and solution form using Z-scan and degenerate four wave mixing (DFWM) techniques. Experiments were performed using Q-switched Nd: YAG laser with nanosecond pulses at 532 nm. Investigations revealed that the palladium metal–organic complex possesses nonlinear absorption coefficient βeff which is of the order of 10−9 m/W due to reverse saturable absorption (RSA) and negative nonlinear refractive index (self-defocusing) n2 which is of the order of 10−9 esu. The real and imaginary parts of the third-order nonlinear optical susceptibility (χ(3)) were found to be of the order of 10−11 esu. The second-order hyperpolarizability (γh) was estimated to be of the order of 10−30 esu. The results of pump–probe experiments show that the switch-on and switch-off times of the palladium metal–organic complex were in μs for different pump intensities and the energy dependent transmission studies reveal better limiting property of the compound at nanosecond regime. Thus the nonlinear response of the material suggests that it has a potential application for high sensitive photonic devices.

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► Newly synthesized Pd metal–organic doped PMMA films were fabricated by spin-coating method.
► Third-order nonlinear optical susceptibility is of the order of 10−11 esu.
► Metal–organic complex posses large NLA due to RSA, which exhibits strong optical power limiting effect.
► All-optical switching action of PdL based on RSA is discussed and modulation of the probe intensity was determined.
► The investigated palladium complex is a potential candidate for new optical device applications.