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O: Fachverband Oberflächenphysik
O 24: Plasmonics and Nanooptics III: Light-Matter Interaction and Spectroscopy
O 24.5: Talk
Tuesday, March 19, 2024, 11:30–11:45, MA 042
Observation of Anisotropic Phonon Polariton Propagation with Sum-Frequency Generation Microscopy — •Richarda Niemann1, Sören Wasserroth1, Gonzalo Álvarez-Pérez2, Javier Martín-Sánchez2, Pablo Alonso-Gonzáles2, Martin Wolf1, and Alexander Paarmann1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin — 2Department of Physics, University of Oviedo, Oviedo 33006, Spain
Surface phonon polaritons (SPhPs) have been proven an interesting tool in the field of nanophotonics as they can be used in applications in the mid- to far-IR regime with lower losses than their plasmonic counterparts.[1] Commonly, propagating SPhPs are imaged using tip-based near-field techniques like scanning near-field optical microscopy which suffer from long image acquisition times due to the point-scanning approach and thus are often limited to only a few selected frequencies.[2] Here, we observe propagating phonon polaritons launched on an m-cut AlN substrate in a far-field approach by interferometric wide-field imaging. Our technique of sum-frequency generation (SFG) spectro-microscopy offers high spatial and spectral resolution at rapid acquisition speed.[3] We are able to extract the anisotropic dispersion of the propagating polaritons and compare them to numerical simulations.
[1] Caldwell et al., Nanophotonics 4, 1 (2015)
[2] Barnett et al., Appl. Phys. Lett. 120, 211107 (2022)
[3] Niemann et al., Appl. Phys. Lett. 120, 131102 (2022)
Keywords: phonon polaritons; sum-frequency generation; microscopy; interferometry; nonlinear