Nonlinear Optical Behavior and Optical Power Limiting Characteristics of Peripheral Symmetrical and Non-symmetrical Zinc Phthalocyanines with Nanosecond Pulsed Excitation

Abstract In this study, the optical nonlinear absorption and optical limiting performances of symmetrical and non-symmetrical zinc phthalocyanines in tetrahydrofuran (THF) solution were conducted by the open aperture z-scanning technique. A new non-symmetrically substituted metallophthalocyanine, namely 2(3)-[(4-nitrophenyl)ethynyl]-{9(10),16(17),23(24)-tris-(3,5-bis(trifluoromethyl)phenoxy)-phthalocyaninato}zinc(II) (1b), was synthesized and then characterized by applying different spectroscopic methods, such as FT-IR, 1H NMR and MALDI-TOF spectroscopy. According to the literature, {2(3),9(10),16(17),23(24)-tetrakis-(3,5-bis(trifluoromethyl)phenoxy)-phthalocyaninato}zin(II) (1a), {2,3,9,10,16,17,23,24-octakis-(3,5-bis(trifluoromethyl)phenoxy)-phthalocyaninato}zinc(II) (2a) and 2(3)-[(4-nitrophenyl)ethynyl]-{9,10,16,17,23,24-hexakis-(3,5-bis(trifluoromethyl)phenoxy)-phthalocyaninato}zinc(II) (2b) were prepared. The effect of the symmetry and substituent’s number on the nonlinear behavior was determined. A Nd:YAG laser, nanosecond pulsed at 532 nm, was used as the excitation source. The measurements of the input-output power and the nonlinear transmission properties were carried out for different excitation power values and different concentrations of the phthalocyanines in the THF solution. The nonlinear absorption coefficient of β and the imaginary part of the third order nonlinear susceptibility of the medium ( X 3 ) were found to be strongly dependent on the concentration. All the zinc phthalocyanine complexes showed good optical limiting performances, attributed to a reverse saturable absorption (RSA) process. The results indicate that the zinc phythcyanine complexes are promising candidates for optical limiting materials.