Nature Communications (Dec 2019)
Observation of strong nonlinear interactions in parametric down-conversion of X-rays into ultraviolet radiation
Abstract
Here, the authors report parametric down-conversion of X-rays into long wavelength radiation in gallium arsenide and lithium niobate crystals, with efficiencies about 4 orders of magnitude stronger than the efficiencies measured in any material studied previously. They explore the lack of inversion symmetry as a possible physical mechanism.