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HL: Fachverband Halbleiterphysik

HL 18: Focus Session: Nanoscale Light-matter Interaction I

HL 18.5: Hauptvortrag

Dienstag, 18. März 2025, 11:45–12:15, H17

Programmable polariton nanophotonics using phase-change materials — •Thomas Taubner — I. Institute of Physics (IA), RWTH Aachen University, Aachen, Germany

Tailoring light-matter interaction is essential to realize nanophotonic components and can be achieved with polaritons, an excitation of photons coupled to charges in metals and semiconductors. Adding a thin layer of Phase-change material (PCM) leads to stronger polariton confinement and enables optical writing of resonator structures based on a change in the refractive index [1]. The recently introduced plasmonic PCM In₃SbTe₂ (IST) can be reversibly switched from an amorphous dielectric to a crystalline metallic state, enabling optically re-writable IR nanoantennas and metasurfaces [2].

Here, we show direct optical writing of resonators for surface phonon polariton (SPhP) by crystallizing IST on top of a SiC crystal and investigate the strongly confined resonance modes with s-SNOM. Reconfiguring the size and shape of the resonators leads to mode confinements of λ/35 [3]. We also demonstrate the real-space imaging of IR surface plasmon polaritons on bulk doped semiconductors, enabled by the strong polariton confinement induced by the added thin dielectric PCM layer [4]. Our concept allows for the rapid prototyping of reconfigurable structures for polaritonics, especially useful with anisotropic 2d materials.

[1] Li et al., Nat. Mat. 15, 870 (2016) [2] Heßler et al. Nat. Com. 12, 924 (2021) [3] Conrads et al. Nat. Com. 15, 3472 (2024) [4] Conrads et al. Sci. Adv. under review

Keywords: polaritons; near-field microscopy; SNOM; phase-change material