Confinement of surface state electrons in Fabry-Perot resonators

Ag(111) surface state electrons have been confined in symmetric and asymmet ric Fabry-Perot resonators formed by two atomically parallel step edges. Th e local density of states in the resonators has been measured by means of l ow-temperature scanning tunneling spectroscopy and can perfectly be explain ed with a simple Fabry-Perot-like model. The energy dependent reflection am plitudes and scattering phase shifts of the different kinds of Ag(111) step edges have been determined with high accuracy. The model character of the resonators opens up quantitative electron scattering experiments at test st ructures brought into the resonator.