Kinoform diffractive lenses for efficient nano-focusing of hard X-rays (original) (raw)
Related papers
High-efficiency zone-plate optics for multi-keV X-ray focusing
Journal of Synchrotron Radiation, 2014
High-efficiency nanofocusing of hard X-rays using stacked multilevel Fresnel zone plates with a smallest zone width of 200 nm is demonstrated. The approach is to approximate the ideal parabolic lens profile with two-, three-, four- and six-level zone plates. By stacking binary and three-level zone plates with an additional binary zone plate, the number of levels in the optical transmission function was doubled, resulting in four- and six-level profiles, respectively. Efficiencies up to 53.7% focusing were experimentally obtained with 6.5 keV photons using a compact alignment apparatus based on piezoelectric actuators. The measurements have also been compared with numerical simulations to study the misalignment of the two zone plates.
Advances in X-Ray/EUV Optics and Components VIII, 2013
Hard x-ray scanning microscopy relies on small and intensive nanobeams. Refractive x-ray lenses are well suited to generate hard x-ray beams with lateral dimensions of 100 nm and below. The diffraction limited beam size of refractive x-ray lenses mainly depends on the focal length and the attenuation inside the lens material. The numerical aperture of refractive lenses scales with the inverse square root of the focal length until it reaches the critical angle of total reflection. We have used nanofocusing refractive x-ray lenses made of silicon to focus hard x-rays at 8 and 20 keV to (sub-)100 nm dimensions. Using ptychographic scanning coherent diffraction imaging we have characterized these nanobeams with high accuracy and sensitivity, measuring the full complex wave field in the focus. This gives access to the full caustic and aberrations of the x-ray optics.
Hard X-ray Diffraction-Limited Nanofocusing with Kirkpatrick-Baez Mirrors
Japanese Journal of Applied Physics, 2005
Nanofocused X-ray beams are necessary for nanometer-scale spatial microscopy analysis. X-ray focusing using a Kirkpatrick-Baez setup with two total reflection mirrors is a promising method, allowing highly efficient and energy-tuneable focusing. In this paper, we report the development of ultraprecise mirror optics and the realization of a nanofocused hard-X-ray beam. Fabricated mirrors having a figure accuracy of 2 nm peak to valley height give ideal diffraction-limited focusing at the hard Xray region. The focal size, defined as the full width at half maximum in the intensity profile, was 36 nm  48 nm at an X-ray energy of 15 keV.
Aberration correction for hard x-ray focusing at the nanoscale
Advances in X-Ray/EUV Optics and Components XII, 2017
We developed a corrective phase plate that enables the correction of residual aberration in reflective, diffractive, and refractive X-ray optics. The principle is demonstrated on a stack of beryllium compound refractive lenses with a numerical aperture of 0.49 × 10 −3 at three different synchrotron radiation and x-ray free-electron laser facilities. By introducing this phase plate into the beam path, we were able to correct the spherical aberration of the optical system and improve the Strehl ratio of the optics from 0.29(7) to 0.87(5), creating a diffraction-limited, large aperture, nanofocusing optics that is radiation resistant and very compact.
Hard x-ray nanoprobe based on refractive x-ray lenses
Applied Physics Letters, 2005
Based on nanofocusing refractive x-ray lenses a hard x-ray scanning microscope is currently being developed and is being implemented at beamline ID13 of the European Synchrotron Radiation Facility ͑Grenoble, France͒. It can be operated in transmission, fluorescence, and diffraction mode. Tomographic scanning allows one to determine the inner structure of a specimen. In this device, a monochromatic ͑E = 21 keV͒ hard x-ray nanobeam with a lateral extension of 47ϫ 55 nm 2 was generated. Further reduction of the beam size to below 20 nm is targeted.
Characterization of a 20-nm hard X-ray focus by ptychographic coherent diffractive imaging
Proceedings of SPIE - The International Society for Optical Engineering, 2011
Recent advances in the fabrication of diffractive X-ray optics have boosted hard X-ray microscopy into spatial resolutions of 30 nm and below. Here, we demonstrate the fabrication of zone-doubled Fresnel zone plates for multi-keV photon energies (4-12 keV) with outermost zone widths down to 20 nm. However, the characterization of such elements is not straightforward using conventional methods such as knife edge scans on well-characterized test objects. To overcome this limitation, we have used ptychographic coherent diffractive imaging to characterize a 20 nm-wide X-ray focus produced by a zone-doubled Fresnel zone plate at a photon energy of 6.2 keV. An ordinary scanning transmission X-ray microscope was modified to acquire the ptychographic data from a strongly scattering test object. The ptychographic algorithms allowed for the reconstruction of the image of the test object as well as for the reconstruction of the focused hard X-ray beam waist, with high spatial resolution and dynamic range. This method yields a full description of the focusing performance of the Fresnel zone plate and we demonstrate the usefulness ptychographic coherent diffractive imaging for metrology and alignment of nanofocusing diffractive X-ray lenses.
Diffractive-Refractive Optics for Focusing Hard X-Rays Beams
The sagittal focusing of x-ray beam diffracted on symmetrically cut crystals with a longitudinal parabolic groove on their diffraction surfaces has been proved experimentally and the results have been already published. This kind of focusing is based on the refraction phenomena occurring during Bragg x-ray diffraction. In this paper our new developments in this field are reported. First, it was shown experimentally that in some cases a channel-cut crystal monochromator with longitudinal parabolic grooves can be replaced by a single crystal with a round hole drilled parallel to diffracting planes. This substantially simplifies the manufacturing of such a focusing monochromator. Second, it has been experimentally proved that the refraction effect, on which the focusing is based, may be substantially enhanced by cutting the longitudinal parabolic groove into the surface of an asymmetrically cut crystal (or drilling a hole whose axis is tilted with respect to the diffracting planes). A very simple formula describing the focusing properties for this case is derived. Finally, the results of the first experiment on the meridional focusing of x-ray beam diffracted on a crystal with a transversal groove on its surface are reported. Some experimental results are compared with the results of ray-tracing simulations, which were developed for this purpose.
Nanometer focusing of hard x rays by phase zone plates
Review of Scientific Instruments, 1999
Focusing of 8 keV x rays to a spot size of 150 and 90 nm full width at half maximum have been demonstrated at the first-and third-order foci, respectively, of a phase zone plate ͑PZP͒. The PZP has a numerical aperture of 1.5 mrad and focusing efficiency of 13% for 8 keV x rays. A flux density gain of 121 000 was obtained at the first-order focus. In this article, the fabrication of the PZP and its experimental characterization are presented and some special applications are discussed.
Nanofocusing parabolic refractive x-ray lenses
Applied Physics Letters, 2003
Parabolic refractive x-ray lenses with short focal distance can generate intensive hard x-ray microbeams with lateral extensions in the 100 nm range even at a short distance from a synchrotron radiation source. We have fabricated planar parabolic lenses made of silicon that have a focal distance in the range of a few millimeters at hard x-ray energies. In a crossed geometry, two lenses were used to generate a microbeam with a lateral size of 380 nm by 210 nm at 25 keV in a distance of 42 m from the synchrotron radiation source. Using diamond as the lens material, microbeams with a lateral size down to 20 nm and below are conceivable in the energy range from 10 to 100 keV.