Atomic resolution x-ray hologram

Unlike crystals producing sharp peaks under the x-ray diffraction, disordered materials show slowly varying patterns presenting little structural information. This is due to the fact that only the scattering intensity can be recorded, and the loss of the phase information makes the Fourier inversion of the amplitude impossible. However, when an amorphous sample is placed on a crystal, the x-ray intensity diffracted by the assembly can produce a hologram which contains the spatial modulation of both density functions. Therefore, with known crystal structure the electron density of the amorphous specimen can be resolved by holographic technique. Moreover,it is found that only the amorphous scattering data are needed, and the Bragg peak(s) can be dropped. This gives the scheme the same noise tolerance as by the ordinary amorphous diffraction. (C) 1996 American Institute of Physics.