Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 71: Poster Plasmonics and Nanooptics: Fabrication, Characterization and Applications

O 71.2: Poster

Wednesday, March 19, 2025, 18:00–20:00, P2

Investigation of the plasmonic phase-change material In₃SbTe₂ in the near-infrared range — •Hristiyana Kyoseva, Lukas Conrads, Rebecca Rahmel, Gero von Plessen, and Thomas Taubner — I. Institute of Physics (IA), RWTH Aachen University

Phase-change materials (PCMs) provide a suitable platform for active nanophotonics and reconfigurable metasurfaces by enabling reversible switching between two phases with contrasting optical properties [1]. In₃SbTe₂ (IST) is a novel plasmonic PCM which can be switched between an amorphous (dielectric) and a crystalline phase (metallic in the whole infrared (IR) spectrum) with precise laser pulses [2]. The direct writing of micrometer-sized structures into a thin IST film with resonances in the mid-IR (above 5 µm) has been extensively demonstrated [3]; however, smaller structures have not been explored yet due to their challenging fabrication process. Here, we examine the smallest achievable sizes of structures written in IST by spatially overlapping crystallization and amorphization pulses. We investigate the resonances of sub-micrometer rod antenna arrays as they shift to shorter wavelengths (below 4 µm) with decreasing size. We also aim to identify its lower limit set by the refractive index of the surrounding media. Our work paves the way towards sophisticated antenna structures with resonances at shorter wavelengths, broadening the applications of IST as a versatile platform for active nanophotonics. [1] Wuttig et al. Nat. Photon. 11, 465 (2017) [2] Heßler et al., Nat. Com. 12, 924 (2021) [3] Heßler, Conrads et al., ACS Photon. 9, 5 (2022).

Keywords: Phase-change materials; Nanophotonics; Metasurfaces