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Reconfigurable Ultraviolet and High-Energy Visible Dielectric Metamaterials

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journal contribution
posted on 05.02.2019, 00:00 by Behrad Gholipour, Davide Piccinotti, Artemios Karvounis, Kevin F. MacDonald, Nikolay I. Zheludev
Photonic materials with tunable and switchable ultraviolet (UV) to high-energy visible (HEV) optical properties may benefit applications such as sensing, high-density optical memory, beam-steering, adaptive optics, and light modulation. Here, for the first time we demonstrate a nonvolatile switchable dielectric metamaterial operating in the UV–HEV spectral range. Nanograting metamaterials in a layered composite of low-loss ZnS/SiO2 and the chalcogenide phase-change medium germanium–antimony–telluride (Ge2Sb2Te5 or GST) exhibit reflection resonances at UV–HEV wavelengths that are substantially modified by light-induced (amorphous–crystalline) phase transitions in the chalcogenide layer. Despite the presence of the lossy GST, resonance quality factors up to Q ∼ 15 are ensured by the transparency (low losses) of ZnS/SiO2 in the UV–HEV spectral range and values of Q increase as the refractive index of Ge2Sb2Te5 decreases, upon crystallization. Notably, however, this switching leaves resonance spectral positions unchanged.