Fabrication of wedged multilayer Laue lenses

Abstract

We present a new method to fabricate wedged multilayer Laue lenses, in which the angle of diffracting layers smoothly varies in the lens to achieve optimum diffracting efficiency across the entire pupil of the lens. This was achieved by depositing a multilayer onto a flat substrate placed in the penumbra of a straight-edge mask. The distance between the mask and the substrate was calibrated and the multilayer Laue lens was cut in a position where the varying layer thickness and the varying layer tilt simultaneously satisfy the Fresnel zone plate condition and Bragg's law for all layers in the stack. This method can be used to extend the achievable numerical aperture of multilayer Laue lenses to reach considerably smaller focal spot sizes than achievable with lenses composed of parallel layers.

Dose efficient Compton X-ray microscopy

“…Our proposed scanning microscopy technique could take advantage of new high-energy synchrotron light sources based on the multibend-achromat [15] that will provide large coherent fluxes at photon energies above 50 keV. This can be combined with new technologies for hard X-ray nanofocusing [13,14,36,37], to achieve dose-optimized and fast X-ray imaging. An advantage of the high photon energy used for SCXM is that the attenuation length of biological material is large, as is the depth of focus.…”

“…(2)]. The required techniques to fabricate such lenses have recently been demonstrated [36,37]. Being diffractive lenses, the focal length of a MLL varies inversely with wavelength, as shown schematically in Fig.…”

Influence of imperfections in a wedged multilayer Laue lens for the focusing of X-rays investigated by beam propagation method

“…The parameters of the lens used in our simulations are similar to a real lens that was prepared and tested at PETRA III in Hamburg, Germany [6,7]. An off axis wedged MLL lens was simulated starting with n = 322 and ending with n = 5822, meaning that part of the lens between the optical axis and 5 lm height is missing.…”

“…For example, Conley et al [4] used profile coating method in the fabrication of a wedged MLL and Niese et al [5] utilized an additional stress layer to obtain zones inclination. However, it was only recently that a 1D wedged MLL has been fabricated [6] and high numerical aperture performance demonstrated [7].…”

Large Aperture and Wedged Multilayer Laue Lens for X-ray Nanofocusing

“…The first wedge MLL (wMLL), where layer placement not only follows the FZP formula, but is also laterally-graded along the optical axis, was produced in 2006 36 using a figured deposition-flux mask. Shortly thereafter, MLL efforts worldwide explored new fabrication techniques, including the use of alternative materials, 37 38 new deposition processes (pulsed-laser deposition 39 40 as well as novel methods [41][42][43] to incorporate lateral gradients for wMLL fabrication. A tilted MLL consisting of parallel layers was used to focus 12 keV X-rays to a spot of 11.2 nm 44 (FWHM) with 15% efficiency.…”