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O: Fachverband Oberflächenphysik
O 84: Gerhard Ertl Young Investigator Award Competition
O 84.3: Vortrag
Donnerstag, 20. März 2025, 11:30–12:00, H24
Imaging Infrared Materials Excitations with Sum-Frequency Spectro-Microscopy — •Niclas S. Mueller1, Alexander Fellows1, Richarda Niemann1,2, Andrew E. Naclerio2, Ryan A. Kowalski2, Ben John1, Katayoun Gharagozloo-Hubmann3, Soeren Wasserroth1, Guanyu Lu2,4, Joshua D. Caldwell2, Piran R. Kidambi2, Martin Wolf1, Martin Thaemer1, and Alexander Paarmann1 — 1Fritz-Haber-Institute of the Max-Planck-Society, Berlin, Germany — 2Vanderbilt University, Nashville, TN, USA — 3Freie Universitaet Berlin, Berlin, Germany — 4Northwestern University, Evanston, IL, USA
Nonlinear optical microscopy and spectroscopy are powerful tools to characterize interfaces and lower-dimensional materials. Here, I show two examples how we use infrared + visible sum-frequency generation (SFG) to image mid-infrared materials excitations with wide-field optical microscopy. The techniques provide combined spatial and spectral information, with sub-diffractional spatial resolution. 1. We visualize the propagation of infrared phonon polaritons in a metasurface of silicon carbide [1]. Through a combination of microscopy and spectroscopy, we observe the hybridization and strong coupling of propagating and localized polaritons, as well as the activation of edge states. 2. We visualize monolayers of hexagonal boron nitride, which are usually optically invisible. Resonant infrared excitation of phonons and heterodyne sum-frequency imaging enable us to image, both, the local topography and crystal orientation with unprecedented detail.
[1] Niemann, Mueller et al. Advanced Materials 36, 2312507 (2024)
Keywords: nonlinear; phonon polariton; infrared; microscopy; boron nitride