Effect of optical resonances on the second harmonic response from Ag(111) and Ag(110) in solution

Abstract

The wavelength dependence of the second harmonic response from native single crystal silver electrodes is examined for Ag(111) and Ag(110). Both the rotational anisotropy and potential dependence of the second harmonic response are significantly different at the two wavelengths examined, 1064 nm and 532 nm excitation. These differences are attributed to optical resonances between the incident or outgoing radiation and surface electronic or bulk electronic transitions of the native metal. The anisotropy at 532 nm reflects the increased contribution of surface interband transitions as this higher excitation energy. It is proposed that the potential dependence at 532 nm excitation involves resonances with surface electronic states on the metal.