Bragg scattering of x-rays in multiwalled carbon nanotubes

In the past few years it has been shown theoretically that carbon nanotubes coated with various materials have the potential to act as waveguides at x-ray frequencies. At these frequencies the angle of incidence relative to the axis of the nanotube is a few milliradians, creating significant challenges for the experimental confirmation of mode formation. Recent developments in the growth of multiwalled carbon nanotubes with $WS2$ walls suggest that they have the potential to act as Bragg fibers at x-ray frequencies. In this paper we use the scattering matrix method to study mode formation in multiwalled carbon nanotubes coated with gold. It is found that they are capable of acting as Bragg fibers but the wall thickness and the number of bilayers must be increased in order to obtain mode confinement.