Mechanism of reverse saturable absorption in chloro-aluminum phthalocyanine solution studied with Z-scan

Using the Z-scan technique with 532 nm laser pulses of dual widths in the p icosecond regime, we distinguish between two-photon absorption (TPA) and ex cited state absorption (ESA). To account for reverse saturable absorption i n chloroaluminum phthalocyanine dissolved in methanol both TPA and ESA, rat her than either one, need be invoked. (C) 1999 Elsevier Science B.V. All ri ghts reserved.