Publications of the SNOM group
Table of contents
2025
- A. Luferau, A. Pashkin, S. Winnerl, M. Obst, S.C. Kehr, E. Dimakis, T.V.A.G. de Oliveira, L.M. Eng, and Manfred Helm.
"Time-resolved nanospectroscopy of III–V semiconductor nanowires."
Nanoscale Advances (2025).
doi: 10.1039/D5NA00307E - 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, and J.D. Caldwell.
"Ultraconfined THz Phonon Polaritons in Hafnium Dichalcogenides."
arXiv:2502.09909 (2025).
doi: 10.48550/arXiv.2502.09909 - 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and T.V.A.G. de Oliveira.
"Germanium Monosulfide as Natural Platform for Highly Anisotropic THz Polaritons."
ACS Nano 16, 20174 (2022). - 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and S.C Kehr.
"Polarization-dependent near-field phonon nanoscopy of oxides: SrTiO3, LiNbO3, and PbZr0.2Ti0.8O3."
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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and 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, and M. Helm.
"Plasmonic superlensing in doped GaAs."
Nano letters 15, 1057-1061 (2015).
doi: 10.1021/nl503996q
List of all publications of Prof. Eng's group