Benedikt Roesner.jpg

Dr. Benedikt Rösner

Member of the X-ray Optics and Applications Group

Paul Scherrer Institut
Laboratory for Micro- and Nanotechnology
ODRA / 106
5232 Villigen PSI
Switzerland

Telephone: +41 56 310 2454
E-mail: benedikt.roesner@psi.ch



Highlights and Research

Extreme ultraviolet vortices at free electron lasers


Extreme ultraviolet vortices can be described as radiation which carries an orbital angular momentum. In electromagnetic radiation from free electron laser and synchrotron sources, the electric and magnetic field can rotate uniformly clockwise or counterclockwise with respect to the light propagation, resulting in circular polarization. In vortices, it is the phase of the electromagnetic field that rotates around a circularity in a helical fashion. The vortex can be characterized with an integer-numbered topologic charge, which describes how often the wavefront is shifted around 360°.
To demonstrate optical vortices at free electron lasers, we fabricated spiral zone plates, which yield a diffraction pattern with such a phase singularity. The material of choice for the extremely intense EUV radiation of the FERMI free electron laser is silicon. We thus etched spiral zone plates into ultraflat thin silicon membranes, and characterized the radiation using a Hartmann wavefront sensor in the far field.
Viewpoint in APS Physics :: Wavefront Characterization of Optical Vortices - Phys. Rev. X

Beam profiling of free electron laser radiation in the focus of a Fresnel zone plate is a true challenge. An established method to characterize extremely intense beams in the EUV and soft X-ray regime is to shoot imprint craters into a material with well known damage attenuation length and threshold, and to characterize the form of the imprint crater. However, this method is limited to a dynamical range of approx. 100, with the consequence that the X-ray fluence has to be varied to get the full beam profile from maximum intensity to faint beam tails. We now adapted a method known from grayscale lithography of PMMA and treated imprint craters with organic solvents (or developers). In this way, additional material, which is exposed to radiation but not ablated, can be removed. We are able to show that the adapted method is extremely sensitive and enhances the dynamic range for beam profiling by an order of magnitude to 1000.
Beam Profiling by Development of Polymer Imprints - Opt. Express

Soft X-ray microscopy at the 7 nm level


Fresnel zone plates are diffractive lenses widely used in X-ray microscopy. As an intrinsic limit from diffraction, their resolution is approximately in the order of their outermost zone width. This induces a major challenge in nanofabrication to produce smaller and smaller nanostructures striving for better resolution. In recent years, zone dimensions and resolution in X-ray micrscopy have been approaching the 10 nanometre level.
We now aimed for demonstrating resolution beyond 10 nm. While zone plates have been reported on with focal spots well below 10 nm (cp. Mohacsi et al., Sci. Rep. 2017, Döring et al., Opt. Express 2013) reconstructed from the farfield, directly recorded X-ray micrographs have not been obtained so far. We thus fabricated zone plates with iridium zones with 9 nm (see above), and tested their resolution at the Hermes beamline at Soleil and the Pollux beamline at the Swiss Light Source. Indeed, these zone plates prove to be capable of resolving test structures with typical sizes below 10 nm. The following image shows a well-resolved periodic iridium structure with 9 nm line width.
The results are presented at the X-Ray Microscopy Conference in Saskatoon in August 2018. A publication is in preparation.

Single shot, time-resolved demagnetization dynamics at free electron lasers


X-ray free electron lasers exhibit unique capabilities to conduct resonant x-ray spectroscopy techniques on ultrafast time scales. Utilizing diffractive optical elements, the pathway difference inherent to diffraction can be exploited to streak the arrival time of an x-ray probe along a geometric dimension. This concept has been applied in a pioneering experiment in reflection geometry at FLASH with a time resolution of 120 fs: Single-shot Monitoring of Ultrafast Processes via X-ray Streaking at a Free Electron Laser.
Adapting the experiment to a transmission geometry, we investigated demagnetization dynamics of a CoDy film together with collaborators from CNRS, the University Pierre and Marie Curie, and at the FERMI free electron laser, see figure above. The time window reachable with this setup is 1.5 ps, theoratically limited by the wavelenght divided through the speed of light. In practice, the duration of the pump puls of approx. 100 fs is the limiting factor. &BR& Extending this scheme to take advantage of the other spatial dimension, more advanced experiments become possible, such as single-shot, time-resolved spectroscopy (see figure below).
A publication is in preparation.

Nanoscience Foundries and Fine Analysis

nffa-logo.png The European NFFA project sets out a platform to carry out comprehensive projects in nanotechnology research, in particular granting access for scientists to methods in nanofabrication. As scientific backbone of the project, we address bottlenecks in nanoscience research with our partners all over Europe.


Personal Information

Profile.JPG
A detailed CV can be found here.


Publications

2018

B. Rösner, S. Finizio, F. Koch, F. Döring, V. A. Guzenko, A. Kleibert, M. Langer, E. Kirk, M. Meyer, J. L. Ornelas, A. Späth, R. H. Fink, S. Stanescu, S. Swaraj, R. Belkhou, B. Watts, J. Raabe, C. David
7 nm spatial resolution in soft X-ray microscopy and high resolution magnetic imaging
in preparation

C. Svetina, C. David, G. Knopp, C. Milne, R. Mankowsky, M. Beck, C. Cirelli, U. Flechsig, R. Follath, F. Koch, J. Krempasky, A. Kubec, G. Ingold, M. Lebugle, G. Mancini, I. Mochi, B. Pedrini, B. Rösner, J. Rouxel, G. Seniutinas, U. Wagner, S. Zerdane, H.T. Lemke, P. Beaud
Towards X-ray Transient Grating Spectroscopy
Optics Letters, in preparation

C. David, B. Rösner, F. Döring, V. A. Guzenko, F. Koch, M. Lebugle, F. Marschall, G. Seniutinas, J. Raabe, B. Watts, D. Grolimund, Z. Yin, M. Beye, S. Techert, J. Viefhaus, G. Falkenberg, C. Schroer
Diffractive X-ray Optics for Synchrotrons and Free-Electron Lasers
Microscopy and Microanalysis 24 (Suppl. 2), 2018, 264-265
https://doi.org/10.1017/S1431927618013673

F. Döring, F. Marschall, Z. Yin, B. Rösner, M. Beye, P. Miedema, K. Kubiček, L. Glaser, D. Raiser, J. Soltau, V. A. Guzenko, J. Viefhaus, J. Buck, M. Risch, S. Techert, C. David
1D-Full Field Microscopy of Elastic and Inelastic Scattering with Transmission off-axis Fresnel Zone Plates
Microscopy and Microanalysis 24 (Suppl. 2), 2018, 182-183
https://doi.org/10.1017/S1431927618013260

J. L. Ornelas, B. Rösner, A. Späth, R. H. Fink
STXM_deconv - a MATLAB Script for the Deconvolution of STXM Images
Microscopy and Microanalysis 24 (Suppl. 2), 2018, 120-121
https://doi.org/10.1017/S1431927618012990

B. Rösner, F. Koch, F. Döring, V. A. Guzenko, M. Meyer, J. L. Ornelas, A. Späth, R. H. Fink, S. Stanescu, S. Swaraj, R. Belkhou, B. Watts, J. Raabe, C. David
7 nm Spatial Resolution in Soft X-ray Microscopy
Microscopy and Microanalysis 24 (Suppl. 2), 2018, 270-271
https://doi.org/10.1017/S1431927618013697

P. R. Ribič, B. Rösner, D. Gauthier, E. Allaria, F. Döring, L. Foglia, L. Gianessi, N. Mahne, M. Manfredda, C. Masciovecchio, R. Mincigrucci, N. Mirian, E. Principi, E. Roussel, A. Simoncig, S. Spampinati, C. David, G. de Ninno
Extreme-Ultraviolet Vortices from a Free-Electron Laser
Microscopy and Microanalysis 24 (Suppl. 2), 2018, 292-293
https://doi.org/10.1017/S1431927618013806

R. H. Fink, B. Rösner, X. Du, A. Späth, M. Johnson, T. Hawly, B. Watts, J. Raabe, L. Gregoratti, M. Amati
In-operando soft X-ray microspectroscopy of organic electronic devices
Microscopy and Microanalysis 24 (Suppl. 2), 2018, 424-425
https://doi.org/10.1017/S143192761801437X

R. Fallica, B. Watts, B. Rösner, G. D. Giustina, L. Brigo, G. Brusatin, Y. Ekinci
NEXAFS study of chemical changes in hybrid organic-inorganic resists upon exposure
Nanotechnology 29, 2018, 36LT03
https://doi.org/10.1088/1361-6528/aaccd4

B. Rösner, F. Koch, F. Döring, J. Bosgra, V. A. Guzenko, E. Kirk, M. Meyer, J. L. Ornelas, R. H. Fink, S. Stanescu, S. Swaraj, R. Belkhou, B. Watts, J. Raabe, C. David
Exploiting Atomic Layer Deposition for Fabricating Sub-10 nm X-ray Lenses
Microelectronic Engineering 191, 2018, 91-96
https://doi.org/10.1016/j.mee.2018.01.033

A. Cattoni, D. Mailly, O. Dalstein, M. Faustini, G. Seniutinas, B. Rösner, C. David
Sub-10 nm Electron and Helium Ion Beam Lithography Using a Recently Developed Alumina Resist
Microelectronic Engineering 193, 2018, 18-22
https://doi.org/10.1016/j.mee.2018.02.015

M. Graczyk, A. Cattoni, B. Rösner, G. Seniutinas, A. Kvennefors, A. Löfstrand, D. Mailly, C. David, I. Maximov
Nanoimprint Stamps with Ultra-High Resolution: Optimal Fabrication Techniques
Microelectronic Engineering 190, 2018, 73-78
https://doi.org/10.1016/j.mee.2018.01.008

2017

B. Rösner, F. Döring, P. R. Ribič, D. Gauthier, E. Principi, C. Masciovecchio, M. Zangrando, J. Vila-Comamala, G. de Ninno, C. David
High Resolution Beam Profiling of X-ray Free Electron Laser Radiation by Polymer Imprint Development
Optics Express 25, 2017, 30686-30695
https://doi.org/10.1364/OE.25.030686

P. R. Ribič, B. Rösner, D. Gauthier, E. Allaria, F. Döring, L. Foglia, L. Gianessi, N. Mahne, M. Manfredda, C. Masciovecchio, R. Mincigrucci, N. Mirian, E. Principi, E. Roussel, A. Simoncig, S. Spampinati, C. David, G. de Ninno
Extreme-Ultraviolet Vortices from a Free-Electron Laser
Physical Review X 7, 2017, 031036
https://doi.org/10.1103/PhysRevX.7.031036

F. Marschall, Z. Yin, M. Beye, J. Buck, F. Döring, V. A. Guzenko, K. Kubicek, J. Rehanek, D. Raiser, B. Rösner, A. Rothkirch, S. T. Veedu, J. Viefhaus, C. David, S. Techert
Transmission zone plates as analyzers for efficient parallel 2D RIXS-mapping
Scientific Reports 7, 2017, 8849
https://dx.doi.org/10.1038/s41598-017-09052-0

F. Marschall, D. McNally, V. A. Guzenko, B. Rösner, M. Dantz, X. Lu, L. Nue, V. Strocov, T. Schmitt, C. David
Zone plates as imaging analyzers for resonant inelastic x-ray scattering
Optics Express 25, 2017, 15624
https://dx.doi.org/10.1364/OE.25.015624

I. Mohacsi, I. Vartiainen, B. Rösner, M. Guizar-Sicairos, V. A. Guzenko, I. McNulty, R. Winarski, M. V. Holt, C. David
Interlaced zone plate optics for hard X-ray imaging in the 10 nm range
Scientific Reports 7, 2017, 43624
https://dx.doi.org/10.1038/srep43624

2016

B. Rösner, U. Schmidt, R. H. Fink
In-operando studies of Ag-TCNQ nanocrystals using Raman and soft x-ray microspectroscopy
XRM Conference Proceedings 849, 2017, 012016
https://dx.doi.org/10.1088/1742-6596/849/1/012016

K. Ran, B. Rösner, B. Butz, R. H. Fink, E. Spiecker
Switching behaviour of individual Ag-TCNQ nanowires: An in situ transmission electron microscopy study
Nanotechnology 27, 2016, 425703
https://dx.doi.org/10.1088/0957-4484/27/42/425703

2015

B. Rösner, M. Milek, A. Witt, B. Gobaut, P. Torelli, R. H. Fink, M. M. Khusniyarov
Reversible Photoswitching of a Spin-Crossover Molecular Complex in the Solid State at Room Temperature
Angewandte Chemie Int. Ed. 54, 2015, 12976-12980
https://dx.doi.org/10.1002/anie.201504192

B. Rösner, K. Ran, B. Butz, U. Schmidt, E. Spiecker, R. H. Fink
A microspectroscopic insight into the resistivity switching of individual Ag-TCNQ nanocrystals
Physical Chemistry Chemical Physics 17, 2015, 18278-18281
https://dx.doi.org/10.1039/c5cp02207j

N. Zeilmann, B. Rösner, A. Späth, U. Schmidt, R. H. Fink
Nanomorphology in thin films of acetamide end-functionalised quaterthiophene
Thin Solid Films 583, 2015, 108-114
https://dx.doi.org/10.1016/j.tsf.2015.03.066

2014

B. Rösner, D. M. Guldi, J. Chen, A. I. Minett, R. H. Fink
Dispersion and Characterization of Arc Discharge Singe-Walled Carbon Nanotubes - Towards Conducting Transparent Films
Nanoscale 6, 2014, 3695-3703
https://dx.doi.org/10.1039/C3NR05788G

B. Rösner, N. Zeilmann, U. Schmidt, R. H. Fink
Employing microspectroscopy to track charge trapping in operating pentacene OFETs
Organic Electronics 15, 2014, 435-440
https://dx.doi.org/10.1016/j.orgel.2013.12.002

2013

B. Rösner, A. Späth, R. H. Fink
The role of solvation effects in the growth of TCNQ-based charge-transfer salts
Journal of Crystal Growth 380, 2013, 34-38
https://dx.doi.org/10.1016/j.jcrysgro.2013.05.031

J. Forster, B. Rösner, R. H. Fink, L. C. Nye, I. Ivanovic-Burmazovic, K. Kastner, J. Tucher, C. Streb
Oxidation-driven self-assembly gives access to high-nuclearity molecular copper vanadium oxide clusters
Chemical Science 4, 2013, 418-424
https://dx.doi.org/10.1039/C2SC20942J

2011

J. Forster, B. Rösner, M. M. Khusniyarov, C. Streb
Tuning the light absorption of vanadium clusters
Chemical Communications 47, 2011, 3114-3116
https://dx.doi.org/10.1039/c0cc05536k