Crystal Structure and Third-Order Nonlinear Optical Properties Study of Tetraphenylporphyrin and Its Nickle Complex at Wavelength 532 nm and 1064 nm

Tetraphenylporphyrin (TPP) and its nickel(II) (NiTPP) complex have been synthesized, their crystal structures have been determined by means of X-ray single crystal diffraction. The TPP possesses good planarity in the porphyrin core, while in the complex the planarity disappeared. The central nickel(II) ion coordinates with four nitrogen atoms, which constructed a distorted square environment. Their third-order nonlinear optical properties have been studied using Z-scan technique at wavelength 532 nm and 1064 nm in picosecond (ps) domain. At 532 nm nonlinear absorption were observed, TPP shows two-photon absorption (TPA) combined with saturable absorption (SA), while NiTPP shows SA. At 1064 nm nonlinear refraction were observed, the molecular second hyperpolarizability γ of the NiTPP was about 1.4 times larger than that of the TPP.