Femtosecond nonlinear optical response of metallophthalocyanine films

The third-order nonlinear optical properties of copper phthalocyanine (CuPc) and magnesium phthalocyanine (MgPc) films were investigated by femtosecond optical Kerr effect (OKE) and pump-probe techniques. For both CuPc and MgPc, the third-order nonlinear optical susceptibility was enhanced at least by one order of magnitude in comparison with that of the metal-free Pc, and the enhancement effect arises from different mechanisms for both films. From pump-probe measurement, quite different transmittance and decay behavior between CuPc and MgPc films were observed. The CuPc films show an ultrafast decay, while the decay behavior of MgPc film is complicated with several temporal components, which could be explained by the relaxation of singlet excited state.