Efficient sub 100 nm focusing of hard x rays
07 Jun 2005-Review of Scientific Instruments (American Institute of Physics)-Vol. 76, Iss: 6, pp 063709
TL;DR: In this paper, the Kirkpatrick-Baez reflecting mirror was used to focus an x-ray beam with energy of 20.5keV to a spot size as small as 90nm×90nm by a reflecting mirror with a graded multilayer.
Abstract: An x-ray beam with energy of 20.5keV has been efficiently focused down to a spot size as small as 90nm×90nm by a Kirkpatrick–Baez reflecting mirrors device. The first mirror, coated with a graded multilayer, plays both the role of vertical focusing device and monochromator, resulting in a very high flux (2×1011photons∕s) and medium monochromaticity (ΔE∕E∼10−2). Evaluation of the error contributions shows that the vertical focus is presently limited by the mirror figure errors, while the horizontal focus is limited by the horizontal extension of the x-ray source. With a gain in excess of a few million, this device opens up new possibilities in trace element nanoanalysis and fast projection microscopy.
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TL;DR: In this paper, an in situ technique that corrects for wavefront aberrations and allows X-rays to be focused to a spot just 7 nm wide could provide a solution.
Abstract: X-ray sources such as free-electron lasers offer the potential to study matter at unprecedented spatial and temporal resolution. But that potential is limited by the poor quality of conventional X-ray optical elements. An in situ technique that corrects for wavefront aberrations and allows X-rays to be focused to a spot just 7 nm wide could provide a solution.
493 citations
Cites methods from "Efficient sub 100 nm focusing of ha..."
...Here, we describe an in situ wavefront analysis and correction technique to compensate for aberrations in hard-X-ray focusing optic...
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TL;DR: A type of linear zone plate for nanometer-scale focusing of hard x rays, a multilayer Laue lens (MLL), produced by sectioning a multILayer and illuminating it in Laue diffraction geometry, indicates that focusing to 5 nm or smaller with high efficiency should be possible.
Abstract: We report on a type of linear zone plate for nanometer-scale focusing of hard x rays, a multilayer Laue lens (MLL), produced by sectioning a multilayer and illuminating it in Laue diffraction geometry. Because of its large optical depth, a MLL spans the diffraction regimes applicable to a thin Fresnel zone plate and a crystal. Coupled wave theory calculations indicate that focusing to 5 nm or smaller with high efficiency should be possible. Partial MLL structures with outermost zone widths as small as 10 nm have been fabricated and tested with 19.5 keV synchrotron radiation. Focal sizes as small as 30 nm with efficiencies up to 44% are measured.
268 citations
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TL;DR: In this paper, the X-ray nanotomography is used to reconstruct a virtual three-dimensional copy of the object from two-dimensional images of the same object from a range of imaging modalities and length scales.
239 citations
TL;DR: This paper aims at providing an introduction to synchrotron radiation and to the fundamentals of some widely used syn chrotron-based techniques, in particular X-ray absorption, fluorescence and tomography.
Abstract: Spectroscopic approaches to plant and soil sciences have provided important information for several decades. However, many of these approaches suffered from a number of limitations and drawbacks especially in terms of spatial resolution and requirements for sample preparation. The advent of dedicated synchrotron facilities, that allow the exploitation of the particular qualities of synchrotron radiation as a research tool, has revolutionised the way we approach the investigation of nutrients and contaminants in environmental samples. Various synchrotron-based techniques are currently available that permit such investigations in situ and at the molecular level. The continuous development of these techniques is delivering substantial gains in terms of sensitivity and spatial resolution which allows analyses of diluted samples at the sub-micron scale. This paper aims at providing an introduction to synchrotron radiation and to the fundamentals of some widely used synchrotron-based techniques, in particular X-ray absorption, fluorescence and tomography. Furthermore, examples are provided regarding the applications of synchrotron-based techniques in the field of plant, soil and rhizosphere research. Finally, current limitations and future perspectives of synchrotron techniques are discussed.
236 citations
Cites background from "Efficient sub 100 nm focusing of ha..."
...Sub-100 nm focused beams have been achieved with bent mirrors when coated with multilayer to increase its numerical aperture (Hignette et al. 2005)....
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...The two current trends are the development of long beamlines and the use of either refractive lenses or multilayer coated mirrors in the Kirkpatrick–Baez geometry to access high energies (Hignette et al. 2005)....
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TL;DR: In this article, the authors developed a fabrication system for hard x-ray mirrors by developing elastic emission machining, microstitching interferometry, and relative angle determinable stitching interference.
Abstract: Nanofocused x rays are indispensable because they can provide high spatial resolution and high sensitivity for x-ray nanoscopy/spectroscopy. A focusing system using total reflection mirrors is one of the most promising methods for producing nanofocused x rays due to its high efficiency and energy-tunable focusing. The authors have developed a fabrication system for hard x-ray mirrors by developing elastic emission machining, microstitching interferometry, and relative angle determinable stitching interferometry. By using an ultraprecisely figured mirror, they realized hard x-ray line focusing with a beam width of 25nm at 15keV. The focusing test was performed at the 1-km-long beamline of SPring-8.
213 citations
References
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TL;DR: Several conceivable methods for the formation of optical images by x-rays are considered, and a method employing concave mirrors is adopted as the most promising.
Abstract: Several conceivable methods for the formation of optical images by x-rays are considered, and a method employing concave mirrors is adopted as the most promising. A concave spherical mirror receiving radiation at grazing incidence (a necessary arrangement with x-rays) images a point into a line in accordance with a focal length f=Ri/2 where R is the radius of curvature and i the grazing angle. The image is subject to an aberration such that a ray reflected at the periphery of the mirror misses the focal point of central rays by a distance given approximately by S=1.5Mr2/R, where M is the magnification of the image and r is the radius of the mirror face. The theoretically possible resolving power is such as to resolve point objects separated by about 70A, a limit which is independent of the wave-length used. Point images of points and therefore extended images of extended objects may be produced by causing the radiation to reflect from two concave mirrors in series. Sample results are presented.
1,149 citations
TL;DR: In this article, a simple procedure for fabricating refractive lenses that are effective for focusing of X-rays in the energy range 5-40 keV is described, and the problem associated with absorption is minimized by fabricating the lenses from low-atomic-weight materials.
Abstract: THE development of techniques for focusing X-rays has occupied physicists for more than a century. Refractive lenses, which are used extensively in visible-light optics, are generally considered inappropriate for focusing X-rays, because refraction effects are extremely small and absorption is strong. This has lead to the development of alternative approaches1,2 based on bent crystals and X-ray mirrors, Fresnel and Bragg–Fresnel zone plates, and capillary optics (Kumakhov lenses). Here we describe a simple procedure for fabricating refractive lenses that are effective for focusing of X-rays in the energy range 5–40 keV. The problems associated with absorption are minimized by fabricating the lenses from low-atomic-weight materials. Refraction of X-rays by one such lens is still extremely small, but a compound lens (consisting of tens or hundreds of individual lenses arranged in a linear array) can readily focus X-rays in one or two dimensions. We have fabricated a compound lens by drilling 30 closely spaced holes (each having a radius of 0.3 mm) in an aluminium block, and we demonstrate its effectiveness by focusing a 14-keV X-ray beam to a spot size of 8 μm.
973 citations
TL;DR: In this article, the authors report the fabrication of high-efficiency, high-contrast gold and nickel multistep (quaternary) Fresnel zone plates using electron beam lithography.
Abstract: The development of high brilliance X-ray sources coupled with advances in manufacturing technologies has led to significant improvements in submicrometre probes for spectroscopy, diffraction and imaging applications. The generation of a small beam spot size is commonly based on three principles1: total reflection (as used in optical elements involving mirrors or capillaries), refraction (such as in refractive lenses2) and diffraction. The latter effect is employed in Bragg–Fresnel or Soret lenses, commonly known as Fresnel zone plate lenses. These lenses currently give the best spatial resolution, but are traditionally limited to rather soft X-rays—at high energies, their use is still limited by their efficiency. Here we report the fabrication of high-efficiency, high-contrast gold and nickel multistep (quaternary) Fresnel zone plates using electron beam lithography. We achieve a maximum efficiency of 55% for the nickel plate at 7 keV. In addition to their high efficiency, the lenses offer the advantages of low background signal and effective reduction of unwanted diffraction orders. We anticipate that these lenses should have a significant impact on techniques such as microscopy3, micro-fluorescence4 and micro-diffraction5, which require medium resolution (500–100 nm) and high flux at fixed energies.
274 citations
TL;DR: In this paper, the phase zone plate (PZP) was used for focusing 8-kV x rays to a spot size of 150 and 90 nm full width at half maximum.
Abstract: 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 (PZP). 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.
203 citations
TL;DR: In this paper, planar parabolic lenses made of silicon were used to generate hard x-ray microbeams with lateral extensions in the 100 nm range even at a short distance from a synchrotron radiation source.
Abstract: 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.
140 citations