Three-Wave Resonance Grazing Incidence X-Ray Diffraction: A Novel Method for Direct Phase Determination of Surface In-Plane Reflections

Abstract

Three-wave resonance grazing incidence x-ray diffraction is realized for the first time by tuning the x-ray photon energy to match the incident wave vector with the coplanar momentum transfers of crystal surface in-plane reflections. Near the resonance energy, the observed specularly diffracted intensities decreasing at lower energies and increasing at higher energies or vice versa reveal the effects of reflection phases due to the coherent interaction of x-ray surface waves. This experiment thus provides a new way of direct phase determination for surface in-plane reflections.