Nonlinear Optical Properties of Novel Metallophthalocyanines

Detailed measurements of nonlinear optical properties and optical limiting for four phthalocyanine (Pc) derivatives (PcCo, PcCu, PcMn, and PcSi) are reported. The nonlinear optical properties were investigated using a Z-scan technique with a continuous-wave argon-ion laser at 488 and 514.5 nm, and with a 532-nm pulsed Nd:YAG laser. All Pcs exhibited strong nonlinear properties and low optical-limiting thresholds. The nonlinear absorption coefficient, the sign and magnitude of the nonlinear refractive index, and the third-order nonlinear susceptibilities of each compound were calculated. Refractive nonlinear effects are the most dominant for continuous laser excitation and are mainly attributed to thermal effects, whereas the reverse saturation absorption coefficient may have an electronic origin. Threshold values indicated that the Pc derivatives are promising materials for optical-limiting applications.