John Jimmy, Slassi Amine, Sun Jianing, Sun Yifei, Bachelet Romain, Pénuelas José, Saint-Girons Guillaume, Orobtchouk Régis, Ramanathan Shriram, Calzolari Arrigo, Cueff Sébastien
Université de Lyon, Institut des Nanotechnologies de Lyon (INL) UMR 5270 CNRS, École Centrale de Lyon, 36 Avenue Guy de Collongue, Ecully 69134, France.
CNR-NANO Istituto Nanoscienze, Modena I-41125, Italy.
Nanophotonics. 2022 Jun 1;11(17):3913-3922. doi: 10.1515/nanoph-2022-0153. eCollection 2022 Sep.
We theoretically and experimentally demonstrate a strong and tunable optical anisotropy in epitaxially-grown VO thin films. Using a combination of temperature-dependent X-ray diffraction, spectroscopic ellipsometry measurements and first-principle calculations, we reveal that these VO thin films present an ultra-large birefringence (Δ > 0.9). Furthermore, leveraging the insulator-to-metal transition of VO, we demonstrate a dynamic reconfiguration of optical properties from birefringent to hyperbolic, which are two distinctive regimes of anisotropy. Such a naturally birefringent and dynamically switchable platform paves the way for multi-functional devices exploiting tunable anisotropy and hyperbolic dispersion.
我们通过理论和实验证明了外延生长的VO薄膜中存在强烈且可调节的光学各向异性。结合温度相关的X射线衍射、光谱椭偏测量和第一性原理计算，我们发现这些VO薄膜具有超大双折射（Δ>0.9）。此外，利用VO的绝缘体-金属转变，我们展示了光学性质从双折射到双曲线的动态重构，这是两种不同的各向异性状态。这样一个自然双折射且可动态切换的平台为利用可调各向异性和双曲线色散的多功能器件铺平了道路。
