Dynamic x-ray diffraction by a multilayer mirror modulated with a transverse acoustic wave.

Dynamic diffraction of an x-ray plane wave by a multilayer mirror modulated with a transverse acoustic wave is analyzed on the basis of rigorous multiwave mode theory. Particular attention is given to the case when λs > τ. where λs is the acoustic wavelength and τ is the extinction length. It has been derived that with increasing sound amplitude, splitting arises in every point of the kinematic branch interaction for both λs < τ and λs > τ. Accordingly the rocking curve takes the form of separate rows of peaks of Bragg diffraction into separate orders, the widths of the peaks being smaller than the width of the Bragg mirror image without modulation. The widths decrease with increasing modulation amplitude.