Optical Properties of Cu Nanocrystalline-OPAA Composite Film

Optically transparent Cu nanocrystalline/OPAA composite film was successfully prepared by electrode-positing Cu into ordered porous anodic alumina(OPAA) template using constant voltage direct current technique.The morphology,structure,linear optical absorption,third-order optical nonlinearity and ultrafast dynamics of the Cu/OPAA composite were characterized by field emission scanning electron microscope(FESEM),transmission electron microscope(TEM).UV-Vis spectrophotometer,Z-scan technique and femtosecond pump-probe experiment.The results show that Cu nanoparicles have diameters of 40-50nm with face center cubic structure and disperse in the branched pores of the OPAA template,which induce a surface plasmon resonance(SPR) absorption at 584 nm.When the probe optical wavelength is far away from the SPR wavelength,Cu nanocrystalline/OPAA composite film possesses a character of light-induced absorption.When the probe optical wavelength is near the SPR wavelength,it possesses a photo-bleaching character.The composite film has a non-resonant third-order nonlinear susceptibility of 0.73×10-9 esu and a response time of 1.3 ps.