Femtosecond and picosecond nonlinear optical studies of Corroles

We present our results of nonlinear optical properties of Tritolyl Corrole (TTC) and Triphenyl Corrole (TPC) studied in the form of solution using Z-scan technique with 660 nm, ~2 picosecond (ps) pulses and 800 nm, ~40 femtosecond (fs) pulses excitation. Picosecond open-aperture Z-scan data revealed these molecules exhibited strong saturable absorption. These molecules possessed negative nonlinear refractive index (n2). The estimated value of n2 was 6×10-15 cm2/W and 8×10-15 cm2/W for TPC and TTC, respectively. We have recently reported NLO properties of Corroles with 800 nm excitation where they exhibited strong two-photon absorption (2PA) at higher intensities and effective two-photon absorption at lower intensities in the ps regime. Femtosecond open aperture Z-scan studies indicated the presence of strong saturable absorption with effective nonlinear absorption coefficients (β) of ~0.8×10-13 cm/W and ~2.7×10-13 cm/W for TPC and TTC, respectively. We have also estimated the sign and magnitude of real part of third order nonlinearity through the closed aperture scans. We discuss the nonlinear optical performance of these organic molecules.