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Abstract: The nonlinear absorption (NLA) properties of copper phthalocyanine (CuPc) solution in acetone were investigated by the femtosecond open-aperture (OA) Z-scan technique. The reverse saturable absorption (RSA) phenomenon was observed. And the physical mechanism of RSA effect was revealed, which was originated from three-photon absorption. Moreover, the influences of concentration and excitation laser power on the NLA of CuPc solution were studied respectively. Results showed that the RSA effect increased with the increase of sample concentration and excitation laser power. It indicated that the CuPc could be a promising candidate for optical limiting material. [Copyright &y& Elsevier]

Abstract: CuO nanocrystalline thin films are deposited on quartz substrates by pulsed laser deposition. The grown single-phase CuO films are characterized by X-ray diffraction, X-ray photoelectron spectrometer and transmission electron microscopy. The optical nonlinearity of CuO films is investigated by the Z-scan method under a high-repetition-rate (HRR) femtosecond laser (800nm, 50fs, 80MHz). The CuO nanocrystalline films are found to be good optical limiters with a limiting threshold of 0.3GW/cm2 and a damage threshold of 1.65GW/cm2. The possible mechanisms of the optical limiting are also proposed. [Copyright &y& Elsevier]