Reconfigurable Ultraviolet and High-Energy Visible Dielectric Metamaterials.
basic_science · Level V
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- Record sourced from PubMed, PMID 30721072.
- Also identified by DOI 10.1021/acs.nanolett.8b04576.
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Abstract
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/SiO<sub>2</sub> and the chalcogenide phase-change medium germanium-antimony-telluride (Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> 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/SiO<sub>2</sub> in the UV-HEV spectral range and values of Q increase as the refractive index of Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> decreases, upon crystallization. Notably, however, this switching leaves resonance spectral positions unchanged.