Publikationen der SNOM-Gruppe

2025

• R.A. Kowalski, N.S. Mueller, G. Álvarez-Pérez, M. Obst, K. Diaz-Granados, G. Carini, A. Senarath, S. Dixit, R. Niemann, R. B. Iyer, F. G. Kaps, J. Wetzel, J.M. Klopf, I. I. Kravchenko, M. Wolf, T.G. Folland, L.M. Eng, S.C. Kehr, P. Alonso-Gonzalez, A. Paarmann und J.D. Caldwell.
  "Ultraconfined THz Phonon Polaritons in Hafnium Dichalcogenides."
  Nature Materials (2025).
  doi: 10.1038/s41563-025-02345-0
  arXiv:2502.09909 (2025).
  doi: 10.48550/arXiv.2502.09909
• G. Carini, M. Pradhan, E. Gelzinyte, A. Ardenghi, S. Dixit, M. Obst, A.S. Senarath, N.S. Mueller, G. Alvarez-Perez, K. Diaz-Granados, R.A. Kowalski, R. Niemann, F.G. Kaps, J. Wetzel, R. Balasubramanyam Iyer, P. Mazzolini, M. Schubert, J.M. Klopf, J.T. Margraf, O. Bierwagen, M. Wolf, K. Reuter, L.M. Eng, S.C. Kehr, J.D. Caldwell, C. Carbogno, T.G. Folland, M.R. Wagner und A. Paarmann.
  "Spectral tuning of hyperbolic shear polaritons in monoclinic gallium oxide via isotopic substitution."
  arXiv:2507.20896 (2025).
  doi: 10.48550/arXiv:2507.20896
• A. Luferau, A. Pashkin, S. Winnerl, M. Obst, S.C. Kehr, E. Dimakis, T.V.A.G. de Oliveira, L.M. Eng und Manfred Helm.  
  "Time-resolved nanospectroscopy of III–V semiconductor nanowires."
  Nanoscale Advances 7, 3692 (2025).
  doi: 10.1039/D5NA00307E
• L. Abylgazina, I. Senkovska, M. Maliuta, C. Bachetzky, M. Rauche, K. Pöschel, J. Schmidt, M. Isaaxs, D. Morgan, M. Otyepka, E. Otyepkova, M. Mendt, Y.D. More, R. Buschbeck, A. Schneemann, A. Synytska, A. Pööpl, L.M. Eng, J.-C. Tan, E. Brunner und S. Kaskel.
  "The role of surface deformation on responsivity of the pillared layer metal–organic framework DUT-8 (Ni)." 
  Chemical Science 16, 6402  (2025).
  doi: 10.1039/d4sc08223k
• F.H. Feres, F.C.B. Maia, S. Chen, R.A. Mayer, M. Obst, O. Hatem, L. Wehmeier, T. Nörenberg, M.S. Queiroz, V. Mazzotti, J.M. Klopf, S.C. Kehr, L.M. Eng, A.R. Cadore, R. Hillenbrand, R.O. Freitas und I.D. Barcelos.
  "Two-dimensional talc as a natural hyperbolic material,"
  arXiv:2501.17340 (2025).
  doi: 10.48550/arXiv.2501.17340

2024

• C.S.J. Lee, C. Canalias, R. Buschbeck, B. Koppitz, F. Hempel, Z. Amber, L.M. Eng und M. Rüsing.

  "Impact of ion exchange on vibrational modes in Rb-doped KTiOPO₄: A Raman spectroscopy study on the interplay between ion exchange and polarization switching."

  Phys. Rev. B 110, 214115 (2024).
  doi: 10.1103/PhysRevB.110.214115

• R.A. Mayer, L. Wehmeier, M. Torquato, X. Chen, F.H. Feres, F.C.B. Maia, M. Obst, F.G. Kaps, A. Luferau, J.M. Klopf, S.N. Gilbert Corder, H.A. Bechtel, J.C. González, E.R. Viana,
  L.M. Eng, S.C. Kehr, R.O. Freitas und I.D. Barcelos.
  "Paratellurite Nanowires as a Versatile Material for THz Phonon Polaritons."
  ACS Photonics 11, 4323 (2024).
  doi:10.1021/acsphotonics.4c01249
• J. Álvarez-Cuervo, M. Obst, S. Dixit, G. Carini, A. I. F. Tresguerres-Mata, C. Lanza, E. Terán-García, G. Álvarez-Pérez, L. Fernández-Álvarez, K. Diaz-Granados, R. Kowalski, A. S. Senerath, N. S. Mueller, L. Herrer, J.M. De Teresa, S. Wasserroth, J. M. Klopf, T. Beechem, M. Wolf, L.M. Eng, T.G. Folland, A. Tarazaga Martín-Luengo, J. Martín-Sánchez, S.C. Kehr, A.Y. Nikitin, J.D. Caldwell, P. Alonso-González und A. Paarmann.
  "Unidirectional Ray Polaritons in Twisted Asymmetric Stacks."
  Nature Communications 15, 9042 (2024).
  doi:10.1038/s41467-024-52750-3
• F. Bernhardt, S. Gharat, A. Kapp, F. Pfeiffer, R. Buschbeck, F. Hempel, O. Pashkin, S.C. Kehr, M. Rüsing, S. Sanna und L.M. Eng.
  "Lattice dynamics of LiNb1-xTaxO3 solid solutions: Theory and experiment."
  Physica Status Solidi A: Applications and Materials Science 2300968 (2024). doi:10.1002/pssa.202300968
• A. Luferau, M. Obst, S. Winnerl, A. Pashkin, S.C. Kehr, E. Dimakis, F.G. Kaps, O. Hatem, K. Mavridou, L.M. Eng und M. Helm.
  "Hot-Electron Dynamics in a Semiconductor Nanowire under Intense THz Excitation."
  ACS Photonics 11, 3123 (2024).
  doi:10.1021/acsphotonics.4c00433

2023

• F. Kaps, S.C. Kehr und L.M. Eng.
  "Polarization Sensitivity in Scattering-Type Scanning Near-Field Optical Microscopy – Towards Nanoellipsometry."
  Applied Sciences 13, 10429 (2023).
  doi:10.3390/app131810429
• M. Obst, T. Nörenberg, G. Álvarez-Pérez, T.V.A.G. de Oliveira,  J. Taboada-Gutiérrez, F.H. Feres, F.G. Kaps, O. Hatem, A. Luferau, A.Y. Nikitin, J.M. Klopf, P. Alonso-González, S.C. Kehr und L.M. Eng.
  "Terahertz Twistoptics – Engineering Canalized Phonon Polaritons."
  ACS Nano 17, 19313 (2023).
  doi:10.1021/acsnano.3c06477
  Preprint available at: doi:10.48550/arXiv.2308.03343

• J. Matson, S. Wasserroth, X. Ni, M. Obst, K. Diaz-Granados, G. Carini, E. Renzi, E. Galiffi, T.G. Folland, L.M. Eng, J.M. Klopf, S. Mastel, S. Armster, V. Gambin, M. Wolf, S.C. Kehr, A. Alu, A. Paarmann und J. Caldwell.

  "Controlling the Propagation Asymmetry of Hyperbolic Shear Polaritons in Beta-Gallium Oxide."
  Nature Communications 14, 5240 (2023).
  doi:10.1038/s41467-023-40789-7
• F.H. Feres, I.D. Barcelos, A.R. Cadore, L. Wehmeier, T. Nörenberg, R.A. Mayer, R.O. Freitas, L.M. Eng, S.C. Kehr und F.C.B. Maia.
  "Graphene Nano-Optics in the Terahertz Gap."
  Nano Letters 23, 3913 (2023).
  doi:10.1021/acs.nanolett.3c00578

2022

• T. Nörenberg, G. Álvarez-Pérez, M. Obst, L. Wehmeier, F. Hempel, J.M. Klopf, A.Y. Nikitin, S.C. Kehr, L.M. Eng, P. Alonso-González und T.V.A.G. de Oliveira.
  "Germanium Monosulfide as Natural Platform for Highly Anisotropic THz Polaritons."
  ACS Nano 16, 20174 (2022).

  doi:10.1021/acsnano.2c05376

• M. Chen, T.V.A.G. De Oliveira, I. Ilyakov, T. Nörenberg, F. Kuschewski, J.-C. Deinert, N. Awari, A. Ponomaryov, M. Kuntzsch, S.C. Kehr, L.M. Eng, M. Gensch und S. Kovalev.
  "Terahertz-slicing — an all-optical synchronization for 4th generation light sources."
  Optics Express 30, 26955 (2022).
  doi:10.1364/OE.454908

2021

• J. Barnett, L. Wehmeier, A. Heßler, M. Lewin, J. Pries, M. Wuttig, J.M. Klopf, S.C. Kehr, L.M. Eng und T. Taubner.
  "Far-Infrared Near-Field Optical Imaging and Kelvin Probe Force Microscopy of Laser-Crystallized and -Amorphized Phase Change Material Ge₃Sb₂Te₆."
  Nano Letters 21, 9012 (2021).
  doi:10.1021/acs.nanolett.1c02353

• S. Kovalev, K.-J. Tielrooij, J.-C. Deinert, I. Ilyakov, N. Awari, M. Chem, A. Ponomaryov, M. Bawatna, T.V.A.G. de Oliveira, L.M. Eng, K.A. Kuznetsov, D.A. Safronenkov, G.Kh. Itaeva, P.I. Kuznetsov, H.A. Hafez, D. Turchinovich und M. Gensch.
  "Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators."
  npj Quantum Materials 6, 84 (2021).
  doi:10.1038/s41535-021-00384-9

• Z. Yao , X. Chen , L. Wehmeier , S. Xu , Y. Shao , Z. Zeng , F. Liu , A. McLeod , S.N. Gilbert Corder , M. Tsuneto , W. Shi , Z. Wang , W. Zheng , H.A. Bechtel , G.L. Carr , M.C. Martin , A. Zettl , D.N. Basov , X. Chen , L.M. Eng , S.C. Kehr und M. Liu.
  "Probing subwavelength in-plane anisotropy with antenna-assisted infrared nano-spectroscopy."
  Nature Communications 12, 2649 (2021).
  doi:10.1038/s41467-021-22844-3
• F.H. Feres, R.A. Mayer, L. Wehmeier, F.C.B. Maia, E. Viana, A. Malachias, H.A. Bechtel, J.M. Klopf, L.M. Eng, S.C. Kehr, J. González, R. Freitas und I. Barcelos.
  "Sub-diffractional cavity modes of terahertz hyperbolic phonon polaritons in tin oxide."
  Nature Communications 12, 1995 (2021).
  doi:10.1038/s41467-021-22209-w
• T. Nörenberg, L. Wehmeier, D. Lang, S.C. Kehr und L.M. Eng.
  "Compensating for artifacts in scanning near-field optical microscopy due to electrostatics."
  APL Photonics 6, 036102 (2021).
  doi:10.1063/5.0031395 
• T.V.A.G. de Oliveira, T. Nörenberg, G. Álvarez-Pérez, L. Wehmeier, J. Taboada-Gutiérrez, M. Obst, F. Hempel, E.J.H. Lee, J.M. Klopf, I. Errea, A.Y. Nikitin, S.C. Kehr, P. Alonso-González und L.M. Eng.
  "Nanoscale-confined Terahertz Polaritons in a van der Waals Crystal."
  Advanced Materials 33, 2005777 (2021).     
  doi:10.1002/adma.202005777

2020

• H. Amin Pour, L.M. Eng und S.C. Kehr.
  "Spatially confined vector fields at material-induced resonances in near-field- coupled systems."
  Optics Express 28, 32316 (2020).
  doi:10.1364/OE.402893

• S. Messerschmidt, A. Krampf, L. Vittadello, M. Imlau, T. Nörenberg, L.M. Eng und David Emin.
  "Small-Polaron Hopping and Low-Temperature (45–225 K) Photo-Induced Transient Absorption in Magnesium-Doped Lithium Niobate."    
  Crystals 10, 809 (2020).
  doi:10.3390/cryst10090809
• A. Soltani, F. Kuschewski, M. Bonmann, A. Generalov, A. Vorobiev, F. Ludwig, M.M. Wiecha, D. Čibiraitė, F. Walla, S. Winnerl, S.C. Kehr, L.M. Eng, J. Stake und H. Roskos.
  "Direct nanoscopic observation of plasma waves in the channel of a graphene field-effect transistor."
  Light: Science & Applications 9, 97 (2020).
  doi: 10.1038/s41377-020-0321-0
• L. Wehmeier, T. Nörenberg, T.V.A.G. de Oliveira, J.M. Klopf, S.-Y. Yang, L.W. Martin, R. Ramesh, L.M. Eng und S.C. Kehr.
  "Phonon-induced near-field resonances in multiferroic BiFeO₃ thin films at infrared and THz wavelengths."
  Applied Physics Letters 116, 071103 (2020).  
  doi: 10.1063/1.5133116

2019

• M. Chen, J.-C. Deinert, B. Green, Z. Wang, I. Ilyakov, N. Awari, M. Bawatna, S. Germanskiy, T.V.A.G. de Oliveira, G. Geloni, T. Tanikawa, M. Gensch und S. Kovalev.
  "Pulse and field-resolved THz-diagnostics at 4th generation lightsources."
  Optics Express 27, 32360 (2019).
  doi: 10.1364/OE.27.032360
• L. Wehmeier, D. Lang, Y. Liu, X. Zhang, S. Winnerl, L.M. Eng und S.C Kehr.
  "Polarization-dependent near-field phonon nanoscopy of oxides: SrTiO₃, LiNbO₃, and PbZr_0.2Ti_0.8O₃."
  Physical Review B 100, 035444 (2019). 
  doi: 10.1103/PhysRevB.100.035444
• D. Lang, L. Balaghi, S. Winnerl, H. Schneider, R. Hübner, S.C. Kehr, L.M. Eng, M. Helm, E. Dimakis und A. Pashkin.
  "Nonlinear plasmonic response of doped nanowires observed by infrared nanospectroscopy."
  Nanotechnology 30, 084003 (2019). 
  doi: 10.1088/1361-6528/aaf5a7
• B. Kirbus, C. Godau, L. Wehmeier, H. Beccard, E. Beyreuther, A. Haußmann und L. M. Eng.
  "Real-Time 3D Imaging of Nanoscale Ferroelectric Domain Wall Dynamics in Lithium Niobate Single Crystals under Electric Stimuli: Implications for Domain-Wall-Based Nanoelectronic Devices."
  ACS Applied Nano Materials 2, 5787 (2019).
  doi: 10.1021/acsanm.9b01240

2018

• J. Döring, D. Lang, L. Wehmeier, F. Kuschewski, T. Nörenberg, S.C. Kehr und L.M. Eng.
  "Low-temperature nanospectroscopy of the structural ferroelectric phases in single-crystalline barium titanate."
  Nanoscale 10, 18074-18079 (2018).
  doi: 10.1039/C8NR04081H
• T. Firkala, F. Kuschewski, T. Nörenberg, J.M. Klopf, A. Pashkin, H. Foerstendorf, M. Rudolph, S.C. Kehr und L.M. Eng.
  "Near-field optical examination of potassium n-butyl xanthate / chalcopyrite flotation products."
  Minerals 8 (3), 118 (2018).
  doi: 10.3390/min8030118
• S. Kovalev, Z. Wang, J.-C. Deinert, N. Awari, M. Chen, B. Green, S. Germanskiy, T.V.A.G. de Oliveira, J.S. Lee, A. Deac, D. Turchinovich, N. Stojanovic, S. Eisebitt, I. Radu, S. Bonetti, T. Kampfrath und M. Gensch.
  "Selective THz control of magnetic order: new opportunities from superradiant undulator sources."
  Journal of Physics D: Applied Physics 51, 114007 (2018).
  doi: 10.1088/1361-6463/aaac75
• D. Lang, J. Döring, T. Nörenberg, Á. Butykai, I. Kézsmárki, H. Schneider, S. Winnerl, M. Helm, S.C. Kehr und L.M. Eng.
  "Infrared nanoscopy down to liquid helium temperatures."
  Review of Scientific Instruments 89, 033702 (2018).
  doi: 10.1063/1.5016281
• L.M. Eng, F. Kuschewski, J. Döring, L. Wehmeier, Th. de Oliveira, H.-G.g von Ribbeck, D. Lang, B. Green, S. Kovalev, N. Awari, S. Winnerl, M. Helm, M. Gensch und S.C. Kehr.
  "Near-field THz nanoscopy at novel accelerator-based photon sources (Conference Presentation)."
  Proceedings SPIE 10531, Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XI, 105310E.
  doi: 10.1117/12.2289463.5751529139001

2017

• S.C. Kehr, J. Döring, M. Gensch, M. Helm und L.M. Eng.
  "FEL-Based Near-Field Infrared to THz Nanoscopy."
  Synchrotron Radiation News 30 (4), 31-35 (2017). 
  doi: 10.1080/08940886.2017.1338421

• A. Butykai, S. Bordács, I. Kézsmárki, V. Tsurkan, A. Loidl, J. Döring, E. Neuber, P. Milde, S.C. Kehr und L.M. Eng.
  "Characteristics of ferroelectric-ferroelastic domains in Néel-type skyrmion host GaV₄S₈." 
  Scientific Reports 7, 44663 (2017).
  doi: 10.1038/srep44663
• L. Wehmeier, T. Kämpfe, A. Haußmann und L. M. Eng.
  "In Situ 3D Observation of the Domain Wall Dynamics in a Triglycine Sulfate Single Crystal upon Ferroelectric Phase Transition."
  physica status solidi (RRL) - Rapid Research Letters 11, 1700267 (2017).
  doi: 10.1002/pssr.201700267
• A. Haußmann, L. Kirsten, S. Schmidt, P. Cimalla, L. Wehmeier, E. Koch und L. M. Eng. "Three-Dimensional, Time-Resolved Profiling of Ferroelectric Domain Wall Dynamics by Spectral-Domain Optical Coherence Tomography."
  Annalen der Physik 529, 1700139 (2017).
  doi: 10.1002/andp.201700139

2016

• J. Döring, L.M. Eng und S.C. Kehr.
  "Low-temperature piezoresponse force microscopy on barium titanate." 
  Journal of Applied Physics 120, 84103 (2016).
  doi: 10.1063/1.4961523
• F. Kuschewski, H.-G. von Ribbeck, J. Döring, S. Winnerl, L.M. Eng und S.C. Kehr
  "Narrow-band near-field nanoscopy in the spectral range from 1.3 to 8.5 THz."
  Applied Physics Letters 108, 113102 (2016).
  doi: 10.1063/1.4943793
• S.C. Kehr, R.G.P. McQuaid, L. Ortmann, T. Kämpfe, F. Kuschewski, D. Lang, J. Döring, J.M. Gregg und L.M. Eng.
  "A Local Superlens." 
  ACS Photonics 3, 20-26 (2016).
  doi: 10.1021/acsphotonics.5b00365

2015

• F. Kuschewski, S.C. Kehr, B. Green, Ch. Bauer, M. Gensch und L.M. Eng.
  "Optical nanoscopy of transient states in condensed matter." 
  Scientific reports 5 (2015).
  doi: 10.1038/srep12582
• M. Fehrenbacher, S. Winnerl, H. Schneider, J. Döring, S.C. Kehr, L.M. Eng, Y. Huo,  O.G. Schmidt, K. Yao, Y. Liu und M. Helm.
  "Plasmonic superlensing in doped GaAs." 
  Nano letters 15, 1057-1061 (2015).
  doi: 10.1021/nl503996q

Liste aller Publikationen der Arbeitsgruppe von Prof. Eng

Ausgewählte Abschlussarbeiten der SNOM Gruppe

Ausgewählte Konferenzbeiträge der SNOM Gruppe