Interband transitions, surface-barrier photoabsorption, and charge-screening waves observed via optical second-harmonic generation of Cs-covered Cu(111)

The optical second-harmonic generation of Cu(111) has been measured during continuous deposition of Cs using incident light with {λ}=1064 nm from a pulsed Nd:YAG laser. The intensity varies greatly with coverage, showing for multilayer coverages an oscillatory intensity ascribed to dynamic Friedel oscillations, while for monolayer coverages we associate the intensity variations with transitions between surface bands and with vacuum-barrier photoabsorption.