Wavelength dependent studies of nonlinear absorption in zinc meso-tetra(p-methoxyphenyl)tetrabenzoporphyrin (Znmp TBP) using Z-scan technique

We report here, our experimental results and theoretical analysis of the di spersion data of nonlinear absorption in zinc meso-tetra-(p-methoxyphenyl)t etrabenzoporphyrin (ZnmpTBP). Using a ns optical parametric oscillator (OPO ) we obtain the open aperture Z-scan data over the visible region starting from 480 nm to 600 nm. We use a more general five-level model for evaluatin g the excited state parameters like excited state absorption coefficients, two-photon absorption coefficient, etc. Due to its large excited state abso rption cross-sections this material acts as a very good candidate for a bro adband optical limiter in the visible region. Copyright (C) 2001 John Wiley & Sons, Ltd.