Abstract
High energy-resolved (ΔE∼9.5 meV) two-photon photoemission was used to study the electron dynamics of the image potential states on the clean Cu(001) surface. We constructed a system consisting of a picosecond Ti:sapphire laser system and a hemispherical analyzer equipped with a two-dimensional electron detector to achieve high energy resolution. The image states of Cu(001) were clearly resolved up to n＝5, and the energy positions of these states were determined up to n＝7. Linewidth analysis yielded pure dephasing rate for the lowest image states.
