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O: Fachverband Oberflächenphysik

O 90: Sensing, Active Structures and other Applications

O 90.2: Vortrag

Donnerstag, 19. März 2015, 15:15–15:30, MA 144

Active mid-IR plasmonic metasurfaces: Tunable and switchable chirality and flat-surface beam steering — •Xinghui Yin¹, Martin Schäferling¹, Ann-Katrin Michel², Andreas Tittl¹, Matthias Wuttig², Thomas Taubner², and Harald Giessen¹ — ¹4. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart — ²1. Physikalisches Institut (IA), RWTH Aachen, Sommerfeldstr. 14, 52074 Aachen

The first metamaterials were fully static, i.e., their geometrical and therefore optical properties were predefined by their design. In order to gain greater control over the effective material behavior, it is desirable to introduce handles that allow for subsequent tailoring of certain material properties. In this work, we demonstrate a tunable and switchable mid-IR chiral metamaterial that utilizes the particularly transparent representative Ge3Sb2Te6 (GST-326) of the chalcogenide phase change material family. When this material is brought into proximity with a plasmonic nanoantenna, the difference in the dielectric environment leads to a large spectral shift (19%) of the plasmon resonance position. Hence, a suitable combination of this material with a chiral metamaterial leads to a shifting circular dichroism signal. Additionally, we demonstrate that precise design of a passive bias-type layer superimposed on the active metamaterial achieves the effect of enantiomer switching. Furthermore, we explore plasmonic beam steering using active plasmonic metasurfaces to emphasize the versatility of hybrid metamaterials comprising plasmonic elements and phase change materials.