title: Creation of X-Ray Transparency of Matter by Stimulated Elastic Forward Scattering.
abstract: X-ray absorption by matter has long been described by the famous Beer-Lambert law. Here, we show how this fundamental law needs to be modified for high-intensity coherent x-ray pulses, now available at x-ray free electron lasers, due to the onset of stimulated elastic forward scattering. We present an analytical expression for the modified polarization-dependent Beer-Lambert law for the case of resonant core-to-valence electronic transitions and incident transform limited x-ray pulses. Upon transmission through a solid, the resonant absorption and dichroic contrasts are found to vanish with increasing x-ray intensity, with the stimulation threshold lowered by orders of magnitude through a resonant superradiantlike effect. Our results have broad implications for the study of matter with x-ray lasers.
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: J
authors.initials: J
authors.lastname: Stöhr
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Scherz
mesh_terms: D002942:Circular Dichroism / Q000379:methods; D003035:Cobalt / Q000737:chemistry; D004548:Elasticity; D007501:Iron / Q000737:chemistry; D008280:Magnetics / Q000379:methods; D008962:Models, Theoretical; D009532:Nickel / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D003035:Cobalt; D009532:Nickel; D007501:Iron