Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 39: Focus Session: Phonon Polaritons: Opportunities for THz Nanooptics II
O 39.1: Vortrag
Dienstag, 13. März 2018, 14:00–14:15, HE 101
Highly-confined surface phonon polaritons in metal circular cavities fabricated on a phase change material — •Hisashi Sumikura1,2, Andreas Hessler1, Lena Jung1, Martin Lewin1, and Thomas Taubner1 — 1RWTH Aachen University, Aachen, Germany — 2NTT Basic Research Laboratories, Atsugi, Japan
To enhance the interaction between light and nanomaterials, the light field should be concentrated into a small volume while overcoming the diffraction limit. In the mid-infrared region, surface phonon polaritons (SPhPs) confined in optical cavities show their strong field concentration. We have studied on metal circular cavities on SiC [1] and laser-induced dielectric cavities in a phase change material on quartz [2] to achieve SPhP confinement.
In this study, we demonstrate cavity-confined mid-infrared SPhPs in a thin film of germanium-antimonide-telluride (GST) deposited on SiC. Scattering-type scanning near-field optical microscopy showed that a 1-μm-diameter metal circular cavity achieves a strong field concentration of the SPhP with a width of less than 250 nm, that is 1/44 of the wavelength of incident light (11.1 μm). In addition, the thermal annealing of the samples switched the SPhP confinement off with a large detuning of the resonance, which is induced by the change in optical constants of phase-changed GST.
[1] T. Wang, P. Li, B. Hauer, D. N. Chigrin, T. Taubner. Nano Lett. 13, 5051 (2013). [2] P. Li, X. Yang, T. W. W. Mass, J. Hanss, M. Lewin, A-K. U. Michel, M. Wuttig, T. Taubner. Nature Mater. 15, 870 (2016).