Advanced thin film technology for ultrahigh resolution X-ray microscopy

Vila‐Comamala, Joan; Jefimovs, Konstantins; Raabe, Jörg; Pilvi, Tero; Fink, R.; Senoner, Mathias; Maaßdorf, A.; Ritala, Mikko; Dávid, Christian

doi:10.1016/j.ultramic.2009.07.005

Cited by 116 publications

(99 citation statements)

References 21 publications

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“…These imperfections may induce small ring-like artifacts in the RPreconstructed slices that are less evident in PS reconstructions (see SI Text). However, recent improvements in microelectronic engineering resulted in novel methods for manufacturing periodic nanostructures (25,26). With these novel techniques-in particular for large fields of view-a better control on the duty-cycle as well as on the uniformity of the grating can be obtained.…”

Section: Resultsmentioning

confidence: 99%

Low-dose, simple, and fast grating-based X-ray phase-contrast imaging

Zhu

Zhang²,

Wang³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

216

156

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Phase sensitive X-ray imaging methods can provide substantially increased contrast over conventional absorption-based imaging and therefore new and otherwise inaccessible information. The use of gratings as optical elements in hard X-ray phase imaging overcomes some of the problems that have impaired the wider use of phase contrast in X-ray radiography and tomography. So far, to separate the phase information from other contributions detected with a grating interferometer, a phase-stepping approach has been considered, which implies the acquisition of multiple radiographic projections. Here we present an innovative, highly sensitive X-ray tomographic phase-contrast imaging approach based on grating interferometry, which extracts the phase-contrast signal without the need of phase stepping. Compared to the existing phase-stepping approach, the main advantages of this new method dubbed "reverse projection" are not only the significantly reduced delivered dose, without the degradation of the image quality, but also the much higher efficiency. The new technique sets the prerequisites for future fast and low-dose phase-contrast imaging methods, fundamental for imaging biological specimens and in vivo studies.X-ray imaging | differential phase contrast | grating interferometer | tomography O ver the last few decades X-ray imaging has experienced a true revolution. The most striking advancement has been the production of coherent X-ray beams with their intrinsic capability of generating interference signals and, as a consequence, providing access to phase information within the investigated sample. This fact has been very stimulating for the X-ray-imaging community, which had been continually challenged by the frustrating question of how to increase the contrast in X-ray images without increasing the dose imparted to a specimen. It is well known that, different from conventional visible light, the refractive index in X-ray optics is very close to and smaller than unity. In first approximation, for a small and negligible anisotropy in the medium, the index of refraction characterizing the optical properties of a tissue can be expressed-including X-ray absorptionwith its complex form: n ¼ 1-δ-iβ where δ is the decrement of the real part of the refractive index, responsible for the phase shift, while the imaginary part β describes the absorption property of the tissue. In conventional absorption-based radiography, the X-ray phase shift information is usually not used for image reconstruction. However, at photon energies greater than 10 keV and for soft tissues (made up of low-Z elements), the phase shift term plays a more prominent role than the attenuation term because δ is typically three orders of magnitude larger than β (1). As a consequence, phase-contrast modalities can generate significantly greater image contrast compared to conventional, absorptionbased radiography. In fact, far from absorption edges, δ is inversely proportional to the square of the X-ray energy while β decreases as the fourth power of it. Conseq...

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Section: Resultsmentioning

confidence: 99%

Low-dose, simple, and fast grating-based X-ray phase-contrast imaging

Zhu

Zhang²,

Wang³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

216

156

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“…When compared with the conventional FZP manufacturing technique, namely the EBL, ML-FZPs present a number of interesting characteristics. Advantages of EBL-FZPs include currently the highest spatial resolutions among point focusing optics [41,61,62] and easy access to larger diameters in general. They are also conveniently fabricated, via well developed schemes, on flat membranes which makes them easier to align.…”

Section: Discussionmentioning

confidence: 99%

“…This alignment process is similar to that described earlier [40]. To determine the resolution, a Siemens star (X30-30-2 Xradia, USA) with specified smallest features of 30 nm, as well as two 500 and 200 nm thick FIB lamellae sliced from a GaAs/Al 0.7 Ga 0.3 As multilayer sample (L200, BAM, Germany) [41] with certified layer thicknesses, were positioned at the 1st order focal plane and raster scanned over the focus. Right behind the test object, an avalanche photodiode (APD, S2382 Hamamatsu, Japan) was employed to collect the total transmitted light at each sample position corresponding to the pixel values of the image.…”

Section: Soft X-ray Range Experimentsmentioning

confidence: 99%

“…To determine the cut off resolution, a test object with feature sizes in the range of the theoretical resolution limit is required. The BAM-L200 test object fits this requirement very well [41]. In addition, it covers a wide range of structure sizes which can be utilized for the extraction of the contrast transfer function (CTF) defined here as the Michelson [46].…”

Section: Imaging Using Soft X-raysmentioning

confidence: 99%

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Multilayer Fresnel zone plates for high energy radiation resolve 21 nm features at 12 keV

Keskinbora¹,

Robisch²,

Mayer³

et al. 2014

Opt. Express

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X-ray microscopy is a successful technique with applications in several key fields. Fresnel zone plates (FZPs) have been the optical elements driving its success, especially in the soft X-ray range. However, focusing of hard X-rays via FZPs remains a challenge. It is demonstrated here, that two multilayer type FZPs, delivered from the same multilayer deposit, focus both hard and soft X-rays with high fidelity. The results prove that these lenses can achieve at least 21 nm half-pitch resolution at 1.2 keV demonstrated by direct imaging, and sub-30 nm FWHM (fullpitch) resolution at 7.9 keV, deduced from autocorrelation analysis. Reported FZPs had more than 10% diffraction efficiency near 1.5 keV. ©2014 Optical Society of AmericaOCIS codes: (340.7460) X-ray microscopy; (340.0340) X-ray optics; (340.6720) Synchrotron radiation; (340.7480) X-rays, soft x-rays, extreme ultraviolet (EUV); (050.1965) Diffractive lenses; (220.4241) Nanostructure fabrication. References and links1. J. Vila-Comamala, Y. Pan, J. J. Lombardo, W. M. Harris, W. K. S. Chiu, C. David, and Y. Wang, "Zonedoubled Fresnel zone plates for high-resolution hard X-ray full-field transmission microscopy," J. Synchrotron Radiat. 19(5), 705-709 (2012). 2. E. Zschech, C. Wyon, C. E. Murray, and G. Schneider, "Devices, materials, and processes for nanoelectronics: characterization with advanced x-ray techniques using lab-based and synchrotron radiation sources," Adv. Eng. Mater. 13(8), 811-836 (2011 Schütz, "Fast spin-wave-mediated magnetic vortex core reversal," Phys. Rev. B 86(13), 134426 (2012). 5. J. Kirz and C. Jacobsen, "The history and future of X-ray microscopy," J. Phys. Conf. Ser. 186, 012001 (2009). 6. P. Kirkpatrick and A. V. Baez, "Formation of optical images by X-Rays," J. Opt. Soc. Am. 38(9), 766-774 (1948 International Journal of Optics 31(4), 403-413 (1984). 46. A. A. Michelson, Studies in Optics (Dover Publications, Incorporated, 1995. 47. G. R. Morrison, "Phase contrast and darkfield imaging in x-ray microscopy," Proc. SPIE 1741, 186-193 (1993).

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“…X‐ray microscopy emerged as a very strong tool for natural sciences by providing half‐pitch spatial resolutions of about 10 nm1, 2, 3, 4 and high penetration depths combined with structural, chemical, and magnetic contrast 5, 6, 7. The importance of X‐ray microscopy will grow in the near future owing to exciting developments such as the emergence of next generation synchrotron sources,8, 9, 10 new X‐ray free electron lasers (XFEL), high brilliance laboratory X‐ray sources and high harmonic generation sources providing radiation in the extreme ultraviolet (EUV) regime 11.…”

Section: Introductionmentioning

confidence: 99%

3D Nanofabrication of High‐Resolution Multilayer Fresnel Zone Plates

et al. 2018

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Focusing X‐rays to single nanometer dimensions is impeded by the lack of high‐quality, high‐resolution optics. Challenges in fabricating high aspect ratio 3D nanostructures limit the quality and the resolution. Multilayer zone plates target this challenge by offering virtually unlimited and freely selectable aspect ratios. Here, a full‐ceramic zone plate is fabricated via atomic layer deposition of multilayers over optical quality glass fibers and subsequent focused ion beam slicing. The quality of the multilayers is confirmed up to an aspect ratio of 500 with zones as thin as 25 nm. Focusing performance of the fabricated zone plate is tested toward the high‐energy limit of a soft X‐ray scanning transmission microscope, achieving a 15 nm half‐pitch cut‐off resolution. Sources of adverse influences are identified, and effective routes for improving the zone plate performance are elaborated, paving a clear path toward using multilayer zone plates in high‐energy X‐ray microscopy. Finally, a new fabrication concept is introduced for making zone plates with precisely tilted zones, targeting even higher resolutions.

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Advanced thin film technology for ultrahigh resolution X-ray microscopy

Cited by 116 publications

References 21 publications

Low-dose, simple, and fast grating-based X-ray phase-contrast imaging

Low-dose, simple, and fast grating-based X-ray phase-contrast imaging

Multilayer Fresnel zone plates for high energy radiation resolve 21 nm features at 12 keV

3D Nanofabrication of High‐Resolution Multilayer Fresnel Zone Plates

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