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Publications (10 of 79) Show all publications
Akan, R., Frisk, T., Lundberg, F., Ohlin, H., Johansson, U., Li, K., . . . Vogt, U. (2020). Metal-Assisted Chemical Etching and Electroless Deposition for Fabrication of Hard X-ray Pd/Si Zone Plates. Micromachines, 11(3), Article ID 301.
Open this publication in new window or tab >>Metal-Assisted Chemical Etching and Electroless Deposition for Fabrication of Hard X-ray Pd/Si Zone Plates
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2020 (English)In: Micromachines, ISSN 2072-666X, E-ISSN 2072-666X, Vol. 11, no 3, article id 301Article in journal (Refereed) Published
Abstract [en]

Zone plates are diffractive optics commonly used in X-ray microscopes. Here, we present a wet-chemical approach for fabricating high aspect ratio Pd/Si zone plate optics aimed at the hard X-ray regime. A Si zone plate mold is fabricated via metal-assisted chemical etching (MACE) and further metalized with Pd via electroless deposition (ELD). MACE results in vertical Si zones with high aspect ratios. The observed MACE rate with our zone plate design is 700 nm/min. The ELD metallization yields a Pd density of 10.7 g/cm3, a value slightly lower than the theoretical density of 12 g/cm3. Fabricated zone plates have a grid design, 1:1 line-to-space-ratio, 30 nm outermost zone width, and an aspect ratio of 30:1. At 9 keV X-ray energy, the zone plate device shows a first order diffraction efficiency of 1.9%, measured at the MAX IV NanoMAX beamline. With this work, the possibility is opened to fabricate X-ray zone plates with low-cost etching and metallization methods.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
X-ray diffractive optics, zone plate, high aspect ratio nanostructures, metal-assisted chemical etching, electroless deposition
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:kth:diva-273084 (URN)10.3390/mi11030301 (DOI)000526546000073 ()32183040 (PubMedID)2-s2.0-85082883683 (Scopus ID)
Note

QC 20200525

Available from: 2020-05-25 Created: 2020-05-25 Last updated: 2020-05-25Bibliographically approved
Bjorling, A., Kalbfleisch, S., Kahnt, M., Sala, S., Parfeniukas, K., Vogt, U., . . . Johansson, U. (2020). Ptychographic characterization of a coherent nanofocused X-ray beam. Optics Express, 28(4), 5069-5076
Open this publication in new window or tab >>Ptychographic characterization of a coherent nanofocused X-ray beam
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2020 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 28, no 4, p. 5069-5076Article in journal (Refereed) Published
Abstract [en]

The NanoMAX hard X-ray nanoprobe is the first beamline to take full advantage of the diffraction-limited storage ring at the MAX IV synchrotron and delivers a high coherent photon flux for applications in diffraction and imaging. Here, we characterize its coherent and focused beam using ptychographic analysis. We derive beam profiles in the energy range 6-22 keV and estimate the coherent flux based on a probe mode decomposition approach.

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2020
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-271942 (URN)10.1364/OE.386068 (DOI)000514575500062 ()32121735 (PubMedID)2-s2.0-85079351442 (Scopus ID)
Note

QC 20200415

Available from: 2020-04-15 Created: 2020-04-15 Last updated: 2020-04-15Bibliographically approved
Kördel, M., Arsana, K. G., Hertz, H. & Vogt, U. (2020). Stability investigation of a cryo soft x-ray microscope by fiber interferometry. Review of Scientific Instruments, 91(2), Article ID 023701.
Open this publication in new window or tab >>Stability investigation of a cryo soft x-ray microscope by fiber interferometry
2020 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 91, no 2, article id 023701Article in journal (Refereed) Published
Abstract [en]

We present a stability investigation of the Stockholm laboratory cryo soft x-ray microscope. The microscope operates at a wavelength of 2.48 nm and can image biological samples at liquid-nitrogen temperatures in order to mitigate radiation damage. We measured the stability of the two most critical components, sample holder and optics holder, in vacuo and at cryo temperatures at both short and long time scales with a fiber interferometer. Results revealed vibrations in the kHz range, originating mainly from a turbo pump, as well as long term drifts in connection with temperature fluctuations. With improvements in the microscope, earlier stability issues vanished and close-to diffraction-limited imaging could be achieved. Moreover, our investigation shows that fiber interferometers are a powerful tool in order to investigate position-sensitive setups at the nanometer level.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2020
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-271501 (URN)10.1063/1.5138369 (DOI)000519231100001 ()32113420 (PubMedID)2-s2.0-85079089509 (Scopus ID)
Note

QC 20200428

Available from: 2020-04-28 Created: 2020-04-28 Last updated: 2020-05-25Bibliographically approved
Kördel, M., Fogelqvist, E., Carannante, V., Önfelt, B., Reddy, H. K. N., Svenda, M., . . . Hertz, H. (2019). Biological Laboratory X-Ray Microscopy. In: Lai, B Somogyi, A (Ed.), X-Ray Nanoimaging: Instruments and Methods IV. Paper presented at X-Ray Nanoimaging: Instruments and Methods IV 2019; San Diego; United States; 11 August 2019 through 12 August 2019. SPIE - International Society for Optical Engineering, 11112, Article ID 111120T.
Open this publication in new window or tab >>Biological Laboratory X-Ray Microscopy
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2019 (English)In: X-Ray Nanoimaging: Instruments and Methods IV / [ed] Lai, B Somogyi, A, SPIE - International Society for Optical Engineering, 2019, Vol. 11112, article id 111120TConference paper, Published paper (Refereed)
Abstract [en]

Zone-plate-based soft x-ray microscopes operating in the water window allow high-resolution and high-contrast imaging of intact cells in their near-native state. Laboratory-source-based x-ray microscopes are an important complement to the accelerator-based instruments, providing high accessibility and allowing close integration with other cell-biological techniques. Here we present recent biological applications using the Stockholm laboratory water-window x-ray microscope, which is based on a liquid-nitrogen-jet laser-plasma source. Technical improvements to the microscope in the last few years have resulted in increased x-ray flux at the sample and significantly improved stability and reliability. In addition to this, vibrations in key components have been measured, analyzed and reduced to improve the resolution to 25 nm half-period. The biological applications include monitoring the development of carbon-dense vesicles in starving human embryonic kidney cells (HEK293T), imaging the interaction between natural killer (NK) cells and HEK293T target cells, and most recently studying a newly discovered giant DNA virus and the process of viral replication inside a host amoeba. All biological imaging was done on cryo-frozen hydrated samples in 2D and in some cases 3D.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2019
Series
Proceedings of SPIE, ISSN 0277-786X ; 11112
Keywords
X-ray microscopy, water-window, laboratory, resolution, cell imaging, cryo
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-268787 (URN)10.1117/12.2531165 (DOI)000511110600017 ()2-s2.0-85076560867 (Scopus ID)978-1-5106-2918-9 (ISBN)
Conference
X-Ray Nanoimaging: Instruments and Methods IV 2019; San Diego; United States; 11 August 2019 through 12 August 2019
Note

QC 20200224

Available from: 2020-02-24 Created: 2020-02-24 Last updated: 2020-05-06Bibliographically approved
Fernandez, A. R., Johansson, U., Carbone, G., Bjorling, A., Kalbfleisch, S., Stankevic, C., . . . Vogt, U. (2018). NanoMAX Beamline, a nanoprobe beamline for scattering and imaging at MAX IV. ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES, 74, E317-E318
Open this publication in new window or tab >>NanoMAX Beamline, a nanoprobe beamline for scattering and imaging at MAX IV
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2018 (English)In: ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES, ISSN 2053-2733, Vol. 74, p. E317-E318Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
INT UNION CRYSTALLOGRAPHY, 2018
Keywords
Nanofocus, Hard X-ray, diffraction
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-255472 (URN)10.1107/S2053273318090411 (DOI)000474406600487 ()
Note

QC 20190814

Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-14Bibliographically approved
Akan, R., Parfeniukas, K., Vogt, C., Toprak, M. S. & Vogt, U. (2018). Reaction control of metal-assisted chemical etching for silicon-based zone plate nanostructures. RSC Advances, 8(23), 12628-12634
Open this publication in new window or tab >>Reaction control of metal-assisted chemical etching for silicon-based zone plate nanostructures
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2018 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, no 23, p. 12628-12634Article in journal (Refereed) Published
Abstract [en]

Metal-assisted chemical etching (MACE) reaction parameters were investigated for the fabrication of specially designed silicon-based X-ray zone plate nanostructures using a gold catalyst pattern and etching solutions composed of HF and H2O2. Etching depth, zone verticality and zone roughness were studied as a function of etching solution composition, temperature and processing time. Homogeneous, vertical etching with increasing depth is observed at increasing H2O2 concentrations and elevated processing temperatures, implying a balance in the hole injection and silica dissolution kinetics at the gold-silicon interface. The etching depth decreases and zone roughness increases at the highest investigated H2O2 concentration and temperature. Possible reasons for these observations are discussed based on reaction chemistry and zone plate design. Optimum MACE conditions are found at HFH2O2 concentrations of 4.7 M:0.68 M and room temperature with an etching rate of ≈0.7 μm min-1, which is about an order of magnitude higher than previous reports. Moreover, our results show that a grid catalyst design is important for successful fabrication of vertical high aspect ratio silicon nanostructures. 

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
Keywords
Aspect ratio, Charge injection, Hydrofluoric acid, Nanocatalysts, Nanostructures, Plate metal, Processing, Silica, Silicon, X ray diffraction, Etching solutions, Metal-assisted chemical etching, Processing temperature, Reaction chemistry, Reaction parameters, Silica dissolution, Silicon interface, Silicon nano structures, Etching
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-227483 (URN)10.1039/c8ra01627e (DOI)000429450000016 ()2-s2.0-85045188242 (Scopus ID)
Funder
Swedish Research Council
Note

Export Date: 9 May 2018; Article; CODEN: RSCAC; Correspondence Address: Vogt, U.; KTH Royal Institute of Technology, Department of Applied Physics, Biomedical and X-ray Physics, Albanova University CenterSweden; email: uvogt@kth.se; Funding details: VR, Vetenskapsrådet; Funding text: This work was supported by the Swedish Research Council. We thank Adem B. Ergul for help with the cross-section images and Jussi Rahomäki for starting with MACE in our group. QC 20180516

Available from: 2018-05-16 Created: 2018-05-16 Last updated: 2020-02-19Bibliographically approved
Seiboth, F., Schropp, A., Scholz, M., Wittwer, F., Roedel, C., Wuensche, M., . . . Schroer, C. G. (2017). Aberration Correction for Hard X-ray Focusing at the Nanoscale. In: Morawe, C Khounsary, AM Goto, S (Ed.), Advances in X-Ray/EUV Optics and Components XII: . Paper presented at Conference on Advances in XRay/ EUV Optics and Components XII held as part of the SPIE Optics + Photonics Symposium, AUG 08-09, 2017, San Diego, CA. SPIE - International Society for Optical Engineering, Article ID UNSP 103860A.
Open this publication in new window or tab >>Aberration Correction for Hard X-ray Focusing at the Nanoscale
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2017 (English)In: Advances in X-Ray/EUV Optics and Components XII / [ed] Morawe, C Khounsary, AM Goto, S, SPIE - International Society for Optical Engineering, 2017, article id UNSP 103860AConference paper, Published paper (Refereed)
Abstract [en]

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 x 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.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2017
Series
Proceedings of SPIE, ISSN 0277-786X ; 10386
Keywords
x-ray optics, compound refractive lenses, aberration correction, ptychography, wavefront sensing
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-220504 (URN)10.1117/12.2274030 (DOI)000417334200008 ()2-s2.0-85038942600 (Scopus ID)978-1-5106-1230-3 (ISBN)978-1-5106-1229-7 (ISBN)
Conference
Conference on Advances in XRay/ EUV Optics and Components XII held as part of the SPIE Optics + Photonics Symposium, AUG 08-09, 2017, San Diego, CA
Note

QC 20171222

Available from: 2017-12-22 Created: 2017-12-22 Last updated: 2018-01-31Bibliographically approved
Vogt, U., Parfeniukas, K., Stankevic, T., Kalbfleisch, S., Liebi, M., Matej, Z., . . . Johansson, U. (2017). First x-ray nanoimaging experiments at NanoMAX. In: Lai, B Somogyi, A (Ed.), X-Ray Nanoimaging: Instruments and Methods III 2017. Paper presented at X-Ray Nanoimaging: Instruments and Methods III 2017, San Diego, United States, 7 August 2017 through 8 August 2017. SPIE - International Society for Optical Engineering, 10389, Article ID 103890K.
Open this publication in new window or tab >>First x-ray nanoimaging experiments at NanoMAX
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2017 (English)In: X-Ray Nanoimaging: Instruments and Methods III 2017 / [ed] Lai, B Somogyi, A, SPIE - International Society for Optical Engineering, 2017, Vol. 10389, article id 103890KConference paper (Refereed)
Abstract [en]

NanoMAX is a hard x-ray nanoimaging beamline at the new Swedish synchrotron radiation source MAX IV that became operational in 2016. Being a beamline dedicated to x-ray nanoimaging in both 2D and 3D, NanoMAX is the first to take full advantage of MAX IVs exceptional low emittance and resulting coherent properties. We present results from the first experiments at NanoMAX that took place in December 2016. These did not use the final experimental stations that will become available to users, but a temporary arrangement including zone plate and order-sorting aperture stages and a piezo-driven sample scanner. We used zone plates with outermost zone widths of 100 nm and 30 nm and performed experiments at 8 keV photon energy for x-ray absorption and fluorescence imaging and ptychography. Moreover, we investigated stability and coherence with a Ronchi test method. Despite the rather simple setup, we could demonstrate spatial resolution below 50 nm after only a few hours of beamtime. The results showed that the beamline is working as expected and experiments approaching the 10 nm resolution level or below should be possible in the future.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2017
Series
Proceedings of SPIE, ISSN 0277-786X ; 10389
Keywords
X-ray microscopy, x-ray nanoimaging, x-ray zone plates
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-220505 (URN)10.1117/12.2272960 (DOI)000417335200006 ()2-s2.0-85034272848 (Scopus ID)978-1-5106-1236-5 (ISBN)978-1-5106-1235-8 (ISBN)
Conference
X-Ray Nanoimaging: Instruments and Methods III 2017, San Diego, United States, 7 August 2017 through 8 August 2017
Funder
Swedish Research Council
Note

QC 20171222

Available from: 2017-12-22 Created: 2017-12-22 Last updated: 2018-03-09Bibliographically approved
Parfeniukas, K., Giakoumidis, S., Akan, R. & Vogt, U. (2017). High-aspect ratio zone plate fabrication for hard x-ray nanoimaging. In: Morawe, C Khounsary, AM Goto, S (Ed.), Advances in X-Ray/EUV Optics and Components XII: . Paper presented at Conference on Advances in XRay/ EUV Optics and Components XII held as part of the SPIE Optics + Photonics Symposium, AUG 08-09, 2017, San Diego, CA. SPIE - International Society for Optical Engineering, 10386, Article ID UNSP 103860S.
Open this publication in new window or tab >>High-aspect ratio zone plate fabrication for hard x-ray nanoimaging
2017 (English)In: Advances in X-Ray/EUV Optics and Components XII / [ed] Morawe, C Khounsary, AM Goto, S, SPIE - International Society for Optical Engineering, 2017, Vol. 10386, article id UNSP 103860SConference paper (Refereed)
Abstract [en]

We present our results in fabricating Fresnel zone plate optics for the NanoMAX beamline at the fourth-generation synchrotron radiation facility MAX IV, to be used in the energy range of 6-10 keV. The results and challenges of tungsten nanofabrication are discussed, and an alternative approach using metal-assisted chemical etching (MACE) of silicon is showcased. We successfully manufactured diffraction-limited zone plates in tungsten with 30 nm outermost zone width and an aspect ratio of 21:1. These optics were used for nanoimaging experiments at NanoMAX. However, we found it challenging to further improve resolution and diffraction efficiency using tungsten. High efficiency is desirable to fully utilize the advantage of increased coherence on the optics at MAX IV. Therefore, we started to investigate MACE of silicon for the nanofabrication of high-resolution and high-efficiency zone plates. The first type of structures we propose use the silicon directly as the phase-shifting material. We have achieved 6 mu m deep dense vertical structures with 100 nm linewidth. The second type of optics use iridium as the phase material. The structures in the silicon substrate act as a mold for iridium coating via atomic layer deposition (ALD). A semi-dense pattern is used with line-to-space ratio of 1:3 for a so-called frequency-doubled zone plate. This way, it is possible to produce smaller structures with the tradeoff of the additional ALD step. We have fabricated 45 nm-wide and 3.6 mu m-tall silicon/iridium structures.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2017
Series
Proceedings of SPIE, ISSN 0277-786X ; 10386
Keywords
zone plate, high-aspect ratio, etching, RIE, MACE, tungsten, silicon, gold
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-220503 (URN)10.1117/12.2272695 (DOI)000417334200016 ()2-s2.0-85038958242 (Scopus ID)978-1-5106-1230-3 (ISBN)978-1-5106-1229-7 (ISBN)
Conference
Conference on Advances in XRay/ EUV Optics and Components XII held as part of the SPIE Optics + Photonics Symposium, AUG 08-09, 2017, San Diego, CA
Funder
Swedish Research Council, C0242401Knut and Alice Wallenberg Foundation
Note

QC 20171222

Available from: 2017-12-22 Created: 2017-12-22 Last updated: 2018-03-09Bibliographically approved
Stankevic, T., Engblom, C., Langlois, F., Alves, F., Lestrade, A., Jobert, N., . . . Kubsky, S. (2017). Interferometric characterization of rotation stages for X-ray nanotomography. Review of Scientific Instruments, 88(5), Article ID 053703.
Open this publication in new window or tab >>Interferometric characterization of rotation stages for X-ray nanotomography
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2017 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 88, no 5, article id 053703Article in journal (Refereed) Published
Abstract [en]

The field of three-dimensional multi-modal X-ray nanoimaging relies not only on high-brilliance X-rays but also on high-precision mechanics and position metrology. Currently available state-of-the-art linear and rotary drives can provide 3D position accuracy within tens to hundreds of nm, which is often insufficient for high resolution imaging with nanofocused X-ray beams. Motion errors are especially troublesome in the case of rotation drives and their correction is more complicated and relies on the metrology grade reference objects. Here we present a method which allows the characterisation and correction of the radial and angular errors of the rotary drives without the need for a highly accurate metrology object. The method is based on multi-probe error separation using fiber-laser interferometry and uses a standard cylindrical sample holder as a reference. The obtained runout and shape measurements are then used to perform the position corrections using additional drives. We demonstrate the results of the characterization for a piezo-driven small rotation stage. The error separation allowed us to measure the axis runout to be approximately +/-1.25 mu m, and with active runout compensation this could be reduced down to +/-42 nm.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2017
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-210504 (URN)10.1063/1.4983405 (DOI)000402801900036 ()28571450 (PubMedID)2-s2.0-85019598560 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20170704

Available from: 2017-07-04 Created: 2017-07-04 Last updated: 2017-07-04Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4394-0591

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