Idler energy dependence of nonlinear diffraction in X→X+EUV parametric down-conversion

The idler energy dependence was investigated for the rocking curve of nonlinear diffraction in parametric down-conversion of X-rays into extreme ultraviolet. The line shape of the rocking curve changed drastically from a nearly Lorentzian peak to a dip as the idler energy decreased. The rocking curve was analyzed using the Fano formula.