The 2nd Workshop on Science Opportunities with Diffraction-Limited Soft X-rays

15 Apr 2026, 09:00 → 16 Apr 2026, 21:00 US/Pacific

Berkeley, CA, USA

Jörg Schwenke (MAX IV), Aymeric Robert (MAX IV Laboratory)

MAX IV Laboratory, the Advanced Light Source (ALS), and NSLS-II follow up on the soft x-ray workshop of April 2023 (link) by hosting a new workshop  on April 15-16 2026, to continue the collaboration and discussion on opportunities with coherent soft X-rays. Because of the workshop’s scale and format, participation is by invitation only.

The new workshop will highlight beams with Orbital Angular Momentum and X-ray coherence as a topic for long-term collaboration and development. The high coherent flux provided by fourth generation synchrotrons has lead to an increased interest in the soft x-ray OAM beams in recent years. Through this workshop, we aim to promote scientific discussion on the generation and application of these beams, and foster international collaboration.

 

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This workshop is funded by Vetenskapsrådet, the Swedish Research Council (www.vr.se) and the Advanced Light Source (https://als.lbl.gov/),

VR  the major science funding agency in Sweden and the agency that funds MAX IV Laboratory. The Advnced Light Source is funded by the US Department of Energy / Basic Energy Sciences (https://www.energy.gov/science/bes/basic-energy-sciences)

Wednesday 15 April

Welcome

Facilities

Convener: Aymeric Robert (MAX IV Laboratory)

1 MAX IV Laboratory

Speaker: Olof Karis (MAX IV)

2 MAX IV Laboratory

Speaker: Joachim Schnadt (Division of Synchrotron Radiation Research, Lund University)

3 LBNL - ALS

Speaker: Andreas Scholl (Lawrence Berkeley National Lab)

4 Synchrotron SOLEIL

Speaker: Amina Taleb-Ibrahimi (Synchrotron SOLEIL)

10:30 Coffee Break

Beamlines, overview

Convener: Jörg Schwenke

5 Xray OAM Studies at the ALS

Advances in X-ray diffractive optics with nearly arbitrary beam-structuring capabilities open new possibilities for the use of X-rays in probing complex electronic structures in matter. ALS-U and the increased coherent flux from diffraction-limited synchrotrons make the potential for innovative methods with these optics even more attractive. One demonstrated result of tailoring the intensity and phase structure of X-rays is the creation of “twisted X-rays”, or X-ray vortices with orbital angular momentum (OAM) of arbitrary integer multiples of h-bar.

Speaker: Sujoy Roy (Lawrence Berkeley National Laboratory)

6 Recent results and update of instrumentation for soft x ray resonant scattering and coherent imaging at ALBA synchrotron light source

The facilities for soft x-ray resonant scattering and coherent imaging at ALBA synchrotron (presently BOREAS beamline) will be overview, including details on recent and on-going upgrades. The capabilities will be illustrated through a wrap up of recent results by various user teams and the beamline team.

Speaker: Manuel Valvidares (ALBA Synchrotron Light Source)

7 Coherent methods at SoftiMAX

Speaker: Jörg Schwenke (MAX IV Laboratory)

8 Questions / Discussions

12:30 Group photo

12:40 Lunch

Session 3: Optics

Convener: Louisa Pickworth (MAX IV, Lund University)

9 OAM advancements in soft REXS

Recently we demonstrated the ability of managing the OAM generated by dedicated optics, by adding and subtracting, manipulating and analyzing it. Now, we can prove off-axis capabilities going beyond standard treatment, In my talk, I will present some recent results on selected systems.

Speaker: Claudio Mazzoli (BNL)

10 X-ray spin-orbit conversion with resonant magnetic scattering

Photon spin-orbit conversion occurs when a photon's spin angular momentum is converted to orbital angular momentum. This has been observed in the infrared and visible light regimes when scattering from subwavelength birefringent structures. However, the fabrication of such structures for x-ray wavelengths is not feasible. Here, we propose that x-ray spin orbit conversion (XSOC) can be achieved with resonant scattering from an appropriately designed magnetic structure. We have measured scattering from an artificial magnetic vortex structure with circularly polarized light to explore XSOC in the scattering process.

Speaker: Margaret McCarter (University of Kentucky)

11 Manipulation of the orbital angular momentum of soft X-ray beams

Production and manipulation of orbital angular momentum (OAM) of coherent soft X-ray beams is demonstrated utilizing consecutive diffractive optics. OAM addition is observed upon passing the beam through consecutive fork gratings. The OAM of the beam was found to be decoupled from its spin angular momentum (SAM). We argue that practical implementation of angular momentum control by consecutive devices in the X-ray regime opens new experimental opportunities, such as direct measurement of the beam’s OAM without resorting to phase-sensitive techniques, including holography. We also briefly discuss and compare vortex magnetic dichroism measurements in the THz and x-ray ranges.

Speaker: Valery Kiryukhin (Rutgers University)

12 Questions / Discussions

16:00 Coffee break

Applications

Convener: Antoine Islegen-Wojdyla (Lawrence Berkeley National Laboratory)

13 Probing Chiral Condensed Matter with Coherent X‑ray OAM Beams

Chiral and other non‑centrosymmetric materials host a wide range of novel electronic and magnetic phenomena. Coherent X‑ray beams carrying orbital angular momentum (OAM) offer a new and largely unexplored route for probing these systems, with the potential to access symmetry and dynamical information that conventional techniques overlook. By highlighting recent studies of skyrmion lattice dynamics in a chiral magnet, this talk will illustrate both the limitations of current probes and the unique advantages that OAM‑structured X‑rays may bring.

Speaker: Andi Barbour (Brookhaven National Laboratory)

14 Fractional, Dynamic X-ray OAM from Coherent Magnetic Scattering

Square artificial spin-ices (ASI) with topological defects are known to generate orbital angular momentum (OAM) in diffracted X-ray beams. A previous investigation of ASI with even-charge topological defects showed both charge and magnetic X-ray scattering yield photon OAM confined to integer OAM values. Here we show that square ASI’s with an antiferromagnetic ground state yield fractional OAM from magnetic scattering when the topological defect has odd-charge. Fractional OAM beams produced from magnetic scattering can be manipulated by a magnetic field and temperature while the integer OAM from charge scattering remains unaffected. We also show that magnetic fluctuations in the ASI lead to dynamic, fractional OAM. Fractional OAM has potential applications including particle guiding and sorting, high-dimensional photon entanglement, quantum communications, and materials characterization. These findings could open new paths for these applications in the X-ray region.

Speaker: Todd Hastings (University of Kentucky)

15 Questions / Discussions

Brainstorming

Conveners: Antoine Islegen-Wojdyla (Lawrence Berkeley National Laboratory), Aymeric Robert (MAX IV Laboratory), Jörg Schwenke, Louisa Pickworth (MAX IV, Lund University)

19:00 Dinner at hotel

Thursday 16 April

Applications II

Convener: Amina Taleb-Ibrahimi

16 Coherent x-ray studies of spontaneous fluctuations in correlated systems

Rare-earth nickelates (RNiO₃) exhibit a rich interplay of electronic, magnetic, and structural phase transitions, including a metal-to-insulator transition (MIT). While these transitions have been widely studied, spontaneous fluctuations across the phase transition are mostly unexplored. Such fluctuations are increasingly recognized for enabling stochastic functionality in neuromorphic computing. Here, we employ X-ray photon correlation spectroscopy (XPCS) to directly probe structural and magnetic fluctuations in NdNiO₃ and SmNiO₃ thin films. For NdNiO₃, we observe a pronounced slowdown in fluctuation timescales—by an order of magnitude—near the Néel temperature, highlighting strong coupling between structural and magnetic order parameters, independent of epitaxial strain. In contrast, SmNiO₃ shows no such slowdown. Unexpectedly, wavevector-dependent measurements reveal that short-range structural fluctuations are significantly slower (by a factor of 3–5) than long-range fluctuations. Our results demonstrate the power of coherent X-ray techniques in capturing nanoscale fluctuation dynamics and provide new insight into the role of fluctuations in complex oxides.

Speaker: Roopali Kukreja (UC Davis)

17 Probing Protein Dynamics on Microsecond and Nanometer Scales with X-ray Photon Correlation Spectroscopy

Protein dynamics in crowded and hydrated environments span nanometer length scales and microsecond time windows that remain difficult to access with established techniques such as neutron spin echo or NMR relaxometry. Recent advances in coherent X-ray sources have made X-ray Photon Correlation Spectroscopy (XPCS) [1] a powerful addition to this toolbox, enabling direct access to collective protein motion at molecular length scales. In this talk, I will discuss how XPCS has been used to resolve anomalous diffusion and cage effects in ferritin solutions[2], as well as nanoscale stress relaxation in hydrated lysozyme systems [3]. A central theme will be radiation damage not only as a limitation, but as a dynamic process that unfolds on comparable time and length scales as the intrinsic protein motion [4]. By exploiting megahertz repetition rates at XFELs, we demonstrate how protein dynamics can be captured before the onset of beam-induced aggregation, a strategy termed “correlation before aggregation”. These results highlight both the opportunities and limits of using coherent X-rays to study soft biological matter, and illustrate how controlled X-ray illumination can be used to disentangle intrinsic collective dynamics from beam-induced responses. [1] F. Perakis and C. Gutt, Towards molecular movies with X-ray photon correlation spectroscopy, Phys. Chem. Chem. Phys. 22, 19443 (2020). [2] A. Girelli et al., Coherent X-rays reveal anomalous molecular diffusion and cage effects in crowded protein solutions, Nat. Commun. 16, 10814 (2025). [3] M. Bin et al., Coherent X-ray Scattering Reveals Nanoscale Fluctuations in Hydrated Proteins, J. Phys. Chem. B 127, 4922 (2023). [4] M. Reiser et al., Resolving molecular diffusion and aggregation of antibody proteins with megahertz X-ray free-electron laser pulses, Nat. Commun. 13, 5528 (2022).

Speaker: Fivos Perakis (Physics Department, Stockholm University)

18 Imaging Magnetism at the Nanoscale with Dichroic Spectro-ptychography

Understanding and visualizing magnetic configurations at the nanoscale is essential for elucidating the mechanisms governing material functionality and optimizing advanced technologies, from energy-efficient devices to next-generation spintronic architectures. One promising technique that provides high spatial resolution imaging of magnetic configurations is dichroic ptychography, a coherent diffractive imaging technique that reconstructs the polarization-dependent complex transmission function of an object. When combined with spectroscopic measurements, this approach yields quantitative complex dichroic spectra with domain selectivity. In this talk, I will discuss three different approaches to magnetic imaging with X-ray ptychography. First, when combining it with X-ray magnetic circular dichroism to probe ferromagnetic order, we have found that access to the phase dichroism enables the study of samples an order of magnitude thicker than is possible with soft X-ray absorption-based techniques [1], offering access to a wider range of magnetic samples. Second, this phase contrast also provides an advantage when combined with linear dichroism, enabling higher signal-to-noise imaging of compensated magnetic configurations [2]. Beyond simple ferro- or antiferromagnetic order, there is a growing interest in orbitronics, which has emerged as a potential new field in magnetism, motivating efforts to disentangle spin and orbital contributions in magnetic systems [3]. To this end, we have combined dichroic ptychography with vortex beams carrying orbital angular momentum (OAM), and observe indications of coupling between the beam’s OAM and the sample’s ferromagnetic configuration. With these three approaches, we establish X-ray dichroic ptychography as a flexible, quantitative, and high-resolution approach to measure magnetic materials at the nanoscale.

[1] Neethirajan, J. et al. Phys. Rev. X, 14 (2024).
[2] Raboni-Ferreira, M. et al. arXiv e-prints, 2502.08617 (2025).
[3] Fukami, S. et al. Nat. Phys., 1-7 (2025).

Speaker: Marina Raboni Ferreira (Max Planck Institute for Chemical Physics of Solids)

19 Questions / Discussions

10:30 Coffee Break

Applications II

Convener: Claudio Mazzoli

20 Soft x-rays with orbital angular momentum for resonant scattering experiments at the SOLEIL synchrotron

The interest of extending the use of OAM beams from the visible-EUV range to the soft x-rays has been growing steadily over the last few years. Nonetheless, the offer of user accessible beamlines and endstations at synchrotron sources remains limited, especially when one aims at independently varying in a controlled way the spin and the orbital angular momenta of the x-rays. At the SEXTANTS beamline of the SOLEIL synchrotron, we have implemented and commissioned a new setup for absorption and scattering experiments with x-ray beams carrying an orbital angular momentum (OAM). Two alternative methods are available, based on the use of either spiral zone plates or fork gratings devices, and we show how they can be used for both defining and assessing the OAM of an x-ray beam. We also demonstrate that cascading multiple devices enables integer operations on the orbital angular momentum of the resulting x-ray beam. Finally, we report the results of the first resonant scattering pilot experiments in transmission and reflection mode, intended to assess the feasibility of future users’ measurements. The availability of OAM-carrying soft x-rays complements the range of experimental techniques in elastic, resonant and coherent scattering available at the SEXTANTS beamline.

P. Carrara, F. Fortuna, R. Delaunay, J. Vila-Comamala, M. Pancaldi, F. Capotondi, M. Fanciulli, T. Ruchon, N. Jaouen, H. Popescu, M. Sacchi

INSP, CNRS – Sorbonne Université ISMO, CNRS – Université Paris-Saclay LCPMR, CNRS – Sorbonne Université Center for Photon Science, PSI Villigen Elettra – Sincrotrone Trieste, Basovizza CY Cergy – Paris Université LIDYL, CEA – Université Paris-Saclay Synchrotron SOLEIL, Saint-Aubin

Speaker: Maurizio Sacchi (CNRS - INSP and Synchrotron SOLEIL)

21 OAM soft x-rays for ARPES

Speaker: Chris Jozwiak (Advanced Light Source)

22 Orbital Angular Momentum Beams for Probing Chiral Fluctuations

Chiral fluctuations can be found close to a phase transition in helical or spiral magnetic systems. Due to their inherent non-zero magnetic moment measuring fluctuations is non-trivial. Here the possibility to use the orbital angular momentum of x-rays is discussed as an avenue to understanding the entropic driving forces driving these fluctuating frustrated systems.

Speaker: Sophie Morley (Lawrence Berkeley National Laboratory)

23 Questions / Discussions

12:45 Lunch

Session 7: Optics & Instrumentation

Convener: Jörg Schwenke

24 Recent progress in high resolution photon counting detectors with Microchannel Plates

Detectors with Microchannel Plates have found niche applications in soft X-ray UV photon detection, where event counting with high spatial and timing resolution is needed. Different types of readouts for these detectors have been developed over the last several decades. The Timepix readout ASIC placed directly below the MCP in the vacuum is one of the possible readout options. The capability of pixelated Timepix readout to detect many simultaneous events substantially increases the count rate capabilities of these devices to GHz levels. In this talk, we review the possible readout configurations for the MCP detectors, present the recent developments of this photon counting technology and present the results obtained with an MCP detector coupled to a quad Timepix/ Timepix3 and a single-chip Timepix4 readouts. The spatial resolution of this detector can routinely reach ~6 µm values (the size of the MCP pores). This resolution is achieved in real time through the event centroiding. Optimization of detector characteristics needs to be performed to achieve such a high spatial resolution. The timing resolution is ~2 ns with Timepix3 readout and is expected to be ~200 ps with the latest generation Timepix4 readout. A couple of application examples of these detectors at Resonance Inelastic X-ray Scattering (RIXS) and X-ray Photon Correlation Spectroscopy (XPCS) experiments demonstrate the unique capabilities of such devices for certain synchrotron-based techniques. These MCP/Timepix detectors could be very attractive for applications where the photon/electron/ion/neutron counting is required with high spatial and temporal resolution, such as Time of Flight experiments in energy-resolving neutron imaging at spallation neutron sources, fluorescence lifetime imaging and, if adapted for the electron detection, experiments in photoelectron spectroscopy.

Speaker: Anton Tremsin (University of California at Berkeley)

25 Recent OAM Experiments at the ALS

X-ray photons with Orbital Angular Momentum are expected to contribute new sensitivities to a variety of existing synchrotron techniques. Recent experiments at the ALS employing OAM will be discussed.

Speaker: Ryan Evenson (LBNL - ALS)

26 Develeopment of x-ray adaptive optics at the Advanced Light Source

We are developing x-ray adaptive optics at the Advanced Light Source, commissioning wavefront sensors for online wavefront monitoring and characterizing x-ray deformable mirrors.

Speaker: Antoine Islegen-Wojdyla (Lawrence Berkeley National Laboratory)

27 Questions / Discussions

15:45 Coffee Break

Session 8

Convener: Sujoy Roy (Lawrence Berkeley National Laboratory)

28 X-ray spectroscopy using OAM beams

Speaker: David Prendergast (Lawrence Berkeley National Laboratory)

29 Design and fabrication of OAM zone plates

Speaker: Bernhard Luttgenau (Lawrence Berkeley National Lab)

30 Questions / Discussions

Brainstorming

Conveners: Amina Taleb-Ibrahimi, Claudio Mazzoli, Jörg Schwenke, Sujoy Roy (Lawrence Berkeley National Laboratory)

Closing

Conveners: Aymeric Robert (MAX IV Laboratory), Joachim Schnadt (MAX IV Laboratory & Lund University), Jörg Schwenke

19:00 Dinner at Restaurant “Gather"

Restaurant: Gather in Berkeley
2200 Oxford Street
Berkeley, CA
94704