Interferometric probing of thin Niobium layers under high electrical field using the zinc X-ray laser at PALS

We report on interferometric investigation of perturbed surfaces under high electric field by using the 21.2 nm zinc soft X-ray laser operating in a half cavity configuration. dc electric fields of up to 100 MV/m were applied to the surface of a niobium sample. Both positive and negative polarizations of the electric field were examined. Single shot, high-quality X-ray interferograms were recorded with a double-mirror Fresnel interferometer and surface maps were obtained from the experimental data by holographic reconstruction.