Optical Transient Relaxation of an Ag-BaO Composite Thin Filmwith a Supercontinuum Probe

Abstract

The optical transient absorption spectra of an Ag-BaO thin film have beendetected at a wavelength ranging from 400 nm to 1000 nm using the pumpsupercontinuum probe technique with a resolution of 130 fs. We have observed theoptical ultrafast relaxation, in which the electrons near the Fermilevel of Ag nanoparticles were excited to a non-equilibrium state andthen returned to an equilibrium state. The decay time was exponentiallyfitted and varied from 0.67 ps to 4 ps for different components of thesupercontinuum probe. The peak of an unoccupied state for silver atlevel X'4 was estimated to be 1.47 eV above the Fermi level.