Z-SCAN STUDIES ON PORPHYRIN DERIVATIVE

The nonlinear optical properties of a porphyrin derivative (T 3,4, BCE MPP) doped in boric acid glass were probed using the Z-scan technique at different argon-ion laser wavelengths. The nonlinear transmission c haracteristics exhibit saturable absorption at 457.9 nm and 476.5 nm w hile they are dominated by excited state absorption at 488.0 nm. The e xperimental observations are explained by using the four-level saturab le absorber model. Saturation intensity, excited-state absorption cros s-section, light-induced changes in the absorption and the refractive index along with its sign were determined at these argon-ion laser wav elengths. Further, optical limiting characteristics of this sample wer e studied. The observed limiting action is consistent with the Z-scan studies.