Journal Article

PUBDB-2026-01121

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Multimode objective lens for momentum microscopy and x-ray photoemission electron microscopy: Experiments

Tkach, O. (Corresponding author)Extern* ; Fragkos, S. ; Biswas, D. ; Liu, J. ; Fedchenko, O.Extern* ; Lytvynenko, Y.Extern* ; Babenkov, S.Extern* ; Zimmer, D. ; Nguyen, Q. L. ; Chernov, S.Extern*DESY* ; Kutnyakhov, D.XFEL.EU*DESY* ; Scholz, M. ; Wind, N. ; Gloskovskii, A.DESY* ; Pressacco, F.XFEL.EU*DESY* ; Dilling, J.Extern* ; Bruckmeier, L.Extern*DESY* ; Heber, M.XFEL.EU*DESY* ; Wenthaus, L.DESY* ; Brenner, G.DESY* ; Puntel, D. ; Majchrzak, P. E. ; Liu, D. ; Scholz, F.XFEL.EU*DESY* ; Sobota, J. A. ; Koralek, J. D. ; Dakovski, G. ; Mehta, A. ; Sirica, N. ; Hoesch, M.DESY* ; Schlueter, C.DESY* ; Odnodvorets, L. V. ; Mairesse, Y. ; Lee, T.-L. ; Kunin, A. ; Rossnagel, K.DESY* ; Shen, Z. X. ; Elmers, H.-J.Extern* ; Beaulieu, S.Extern* ; Schoenhense, G. (Corresponding author)Extern*

2026
AIP Publishing [Melville, NY]

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Please use a persistent id in citations: doi:10.1063/5.0311293  doi:10.3204/PUBDB-2026-01121

Abstract: A new type of objective lens has recently been proposed for use in x-ray photoemission electron microscopes (XPEEMs) and momentum microscopes. Adding a ring electrode concentric with the extractor allows the field in the gap between the sample and the extractor to be shaped. Forming a lens field in this gap reduces the field strength at the sample by up to an order of magnitude. This mitigates the risk of field emission, particularly for cleaved samples with sharp edges. A retarding field can redirect all slow electrons, thus eliminating the primary contribution to the space-charge interaction. Here, we present the first experimental investigation of the new lens, examining its performance at photon energies ranging from the extreme ultraviolet (XUV) produced by a high-harmonic generation-based source to soft and hard x rays at two synchrotron facilities. The gap lens in a region without electrodes enables large working distances up to 23 mm. Reduced aberrations allow for larger fields of view in both k-space and real-space imaging, with resolutions comparable to those of conventional cathode lenses. However, field strengths are an order of magnitude smaller. The zero-field mode enables the study of 3D structured objects and is, therefore, beneficial for small cleaved samples as well as for operando devices involving top electrodes. The repeller mode reduces space-charge effects but results in a smaller k-field diameter. This reduction ranges from 10% at hard x-ray energies to 50% in the XUV range. The usable energy interval is also reduced by a factor of two. In time-of-flight XPEEM mode, the raw data show a resolution of 250 nm, which can be improved to better than 100 nm through data processing.

Note: We acknowledge DESY (Hamburg, Germany) and DIAMOND(Didcot, UK) for the provision of beamtimes and experimental facil-ities. Parts of this research were carried out at PETRA III, beamlinesP04 and P22, FLASH I, beamline PG2, and at DIAMOND, beamlineI09. Work in Mainz was funded by Bundesministerium für Bildungund Forschung BMBF (Project Nos. 05K22UM1, 05K22UM2, and05K22UM4) and Deutsche Forschungsgemeinschaft DFG throughProject No. SCHO 341/16-1, Transregio SFBs Spin + X TRR175-268565370 (project A02) and Elasto-Q-Mat TRR288–422213477(project B04). Work in Kiel was funded by the BMBF (Project No.05K22FK2) and BMFTR (Project No. 05K25FK2). Work in Frank-furt was funded by the BMFTR (Project No. 05K25RF4) and DFG(Project No. FE 2281/1-1). The instrument at CELIA was fundedby the European Union (ERC Starting Grant ERC-2022-STG No.101076639). We further acknowledge the funding by the IdEx Uni-versity of Bordeaux/Grand Research Program “GPR LIGHT,” byQuantum Matter Bordeaux, AAP CNRS Tremplin, and AAP SMRfrom Université de Bordeaux. This work is part of the ULTRA-FAST and TORNADO projects of PEPR LUMA and was sup-ported by the French National Research Agency, as a part of theFrance 2030 program, under Grant Nos. ANR-23-EXLU-0002 andANR-23-EXLU-0004.S.F. acknowledges the funding from the European Union’sHorizon Europe research and innovation program under the MarieSkłodowska-Curie 2024 Postdoctoral Fellowship No. 101198277(TopQMat). J.A.S., P.E.M., D.P., D.L., and Z.X.S. were supportedby the U.S. Department of Energy, Office of Basic Energy Sciences,Division of Materials Science and Engineering under Contract No.DE-AC02-76SF00515. J.D.K., G.D., and A.M. were funded by theLinac Coherent Light Source (LCLS), SLAC National AcceleratorLaboratory, U.S. Department of Energy, Office of Science, Officeof Basic Energy Sciences under Contract No. DE-AC02-76SF00515.Q.N. acknowledges the support by the SLAC-Stanford QuantumInitiative Q-FARM Bloch Fellowship and U.S. DOE (Grant No. DE-AC02–76SF00515). A.K. acknowledges the funding provided by theArnold and Mabel Beckman Foundation, Beckman Young Inves-tigator Award. Sincere thanks go to Andrew J. Mannix, ZhepengZhang, Lauren Hoang, and Eric Pop (Stanford University, USA) forproviding the WS2 sample.

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)
2. FS-SXQM (FS-SXQM)
3. Experimentebetreuung PETRA III (FS-PET-S)
4. FLASH Wissenschaftlicher Nutzerbetrieb (FS-FLASH-O)
5. FLASH Photonen-Strahlführungen und Optiken (FS-FLASH-B)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. 6G2 - FLASH (DESY) (POF4-6G2) (POF4-6G2)
3. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
4. 05K22UM1 - Verbundprojekt 05K2022 - OperandoHAXPES: Hartröntgen-Photoelektronenmikroskopie im Real- und Impulsraum: Operando Systeme und Quantenmaterialien. Teilprojekt 1. (BMBF-05K22UM1) (BMBF-05K22UM1)
5. 05K22UM2 - Verbundprojekt 05K2022 - 10K-THz-k-ToF: 10K ToF-Impulsmikroskop für FLASH mit Terahertz Anregung und Raumladungsunterdrückung. Teilprojekt 3. (BMBF-05K22UM2) (BMBF-05K22UM2)
6. 05K22UM4 - Verbundprojekt 05K2022 - ToFPAXRIXS: In-situ Kombination von RIXS und ARPES mit Flugzeit basierter Photoelektronen Detektion. Teilprojekt 1. (BMBF-05K22UM4) (BMBF-05K22UM4)

Experiment(s):

1. PETRA Beamline P04 (PETRA III)
2. PETRA Beamline P22 (PETRA III)
3. Measurement at external facility
4. FLASH Beamline PG2 (FLASH)

Appears in the scientific report 2026

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