view article

Figure 1
(a) Schematic of the experimental setup. The X-ray waveguide array (WGA) is positioned at f, which is the distance from the exit of the Kirkpatrick–Baez (KB) device to the sample. The incoming beam with photon energy E and primary intensity I0 is coupled into the Ni/C WGA with working length L, which tailors the near field to the desired shape. The far-field intensity distribution is recorded at a distance of D behind the WGA exit by a two-dimensional pixel detector. (b) A schematic of the structure of the WGA, consisting of seven guiding layers in red (di, [i = 1,\ldots, 7]) and eight cladding layers in purple (cj, [j = 1,\ldots, 8]). After the pre-focus beam has been coupled, the guided mode is produced in the different guiding layers. With the working length L, the exit phase [\varphi _{i}] from the corresponding guiding layers i can be controlled by the variation of the layer thickness di. The parameters at the exit of the WGA can be optimized such that the lines of the exit phase [\varphi _{i}] describe a circle with radius R, resulting in constructive interference in a quasi-focal spot (F) outside the WGA. The phase of the reference sample with length L is [\varphi _{0}], with the corresponding guiding layer d0 and cladding layers c0. (c) Sketch of a slab waveguide with two cladding layers cj and cj+1. Under the influence of the electric field inside the waveguide [[\psi(z,x) = \psi(x)\exp(i\beta z)]], the symmetrical guided modes ([\psi _{{0}},\psi _{{2}}]) and the asymmetrical mode [\psi _{{1}}] propagate inside the guiding layer depending on the different layer thickness di.

Journal logoJOURNAL OF
ISSN: 1600-5767
Follow J. Appl. Cryst.
Sign up for e-alerts
Follow J. Appl. Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds