Investigation on transient relaxation in Ag-BaO composite thin film with pump supercontinuum-probe technique

Optical transient absorption spectra of Ag-BaO thin film were detected in the wavelength range from 450 to 800 nm by the pump supercontinuum-probe technique with 130 fs time resolution. The optical ultrafast relaxation, in which the electrons near the Fermi level of silver nanoparticles were excited to non-equilibrium state and then returned to equilibrium state, was observed. The decay times were exponentially fitted and varied from 4 to 0.67 ps depending on the probe wavelength. The peak unoccupied state, X4', of electrons in silver was estimated to locate at 1.47 eV above the Fermi level. (author)