Hard x-ray nanofocusing by refractive lenses of constant thickness

Abstract

In order to focus light or x rays, the thickness of a refractive lens is typically varied over its aperture. Here, we present a refractive x-ray lens made of lamellae of constant thickness, the refractive lamellar lens. Refractive power is created by a specific bending of the lamellae rather than by a concave lens profile. This very special design has the technological advantage that materials like sapphire or diamond can be used to make lenses by coating techniques. A first lens prototype focused x rays with a photon energy E = 15.25 keV to a lateral beam size of 164 nm × 296 nm full width at half maximum.

Hard x-ray nanoprobe of beamline P06 at PETRA III

“…Besides being a powerful microscopy technique, ptychography is also ideal for characterizing coherent nanobeams. Many experiments at the nanoprobe at P06 have been carried out, characterizing nanofocusing refractive x-ray lenses (NFLs) [8], multilayer Laue lenses (MLL) [9,10], Fresnel zone plates [11] and kinoform diffractive lenses [12], adiabatically focusing lenses (AFLs) [13], and refractive lamellar lenses (RLLs) [14]. The wave field around the focus can be faithfully reconstructed [15], e. g., following in detail the evolution of phase vortices along the caustic of the nanobeam [16].…”

Advances in fabrication of X-ray waveguides

“…The guiding channel cross-sections in the range of 10 to 100 nm and the required length to reach well defined propagation regimes, are extremely challenging in view of fabrication. As in other x-ray focusing optics, such as Fresnel zone plates [9,10,11] or compact refractive lenses [12,13,14], the combination of small wavelength and vanishing differences in the index of refraction n ≈ 1, leads to areas and aspect ratios which are very different from their counterparts in visible light optics. Ideally, an x-ray WG consist of an empty (air filled) channel, embedded in a moderately absorbing material (cladding), with the entrance (front) and exit sides of the channel left open for coupling and decoupling of guided beam.…”

PtyNAMi: Ptychographic Nano-Analytical Microscope at PETRA III: interferometrically tracking positions for 3D x-ray scanning microscopy using a ball-lens retroreflector

“…26,27,[29][30][31] The instrument served as a test bench for developments of methods and instrumentation in x-ray microscopy, pushing ptychography to high-resolution 15 and sensitivity 32 and combining the technique with resonant scattering to obtain chemical contrast. 33 Ptychography was used to characterize various x-ray optics, including refractive optics like adiabatically focusing lenses (AFL), 34,35 refractive lamellar lenses (RLL), 36 and kinoform lenses, 24 and diffractive optics, such as multilayer Laue lenses (MLL) 22,25 and Fresnel zone plates (FZP). 23 To this end, optics characterization schemes 37, 38 and a way to design corrective phase plates for x-ray optics were developed.…”