抄録
Two-photon photoemission spectroscopy is one of the branches of laser photoemission spectroscopy and
is an excellent tool to directly observe unoccupied bands on solid surfaces. Since multiphoton processes
are intrinsically required, pulsed lasers are essential. Thus, the technique has progressed along with the
development of pulsed lasers. In many studies, time-resolved measurements are performed using pumpprobe
techniques. On the other hand, there have been few attempts to pursue energy resolution. In this
paper, we present a high-resolution two-photon photoemission study of band splitting due to spin-orbit
coupling at unoccupied levels on a solid surface.
