Phase-Transition-Driven Hyperbolic Optical Response and Directional Polaritons in Epitaxial VO2 Thin Films
Sapienza University（罗马第一大学）；INFN - Laboratori Nazionali di Frascati（意大利国家核物理研究所-弗拉斯卡蒂国家实验室）；Universita' di Camerino（卡梅里诺大学）；INFN, Turin unit（意大利国家核物理研究所都灵分部）；Rome International Centre for Material Science Superstripes（罗马材料科学超条纹国际中心）；INFN - Sezione di Roma（意大利国家核物理研究所罗马分部）
Maria Chiara Paolozzi, Annalisa D Arco, Ilaria Martinelli, Lorenzo Mosesso, Jacopo Sera, Alessandro D Elia, Augusto Marcelli, Yingxue Chen, Chongwen Zou, Maria … 展开作者
Maria Chiara Paolozzi, Annalisa D Arco, Ilaria Martinelli, Lorenzo Mosesso, Jacopo Sera, Alessandro D Elia, Augusto Marcelli, Yingxue Chen, Chongwen Zou, Maria Cristina Larciprete, Marco Centini, Stefano Lupi, Salvatore Macis
Optical anisotropy in crystalline solids enables direction-dependent light-matter interactions and underpins a variety of advanced photonic functionalities. In this context, Vanadium dioxide (VO2) represents a prototypical material that undergoes a reversible MIT near 67°C, accompanied by pronounced electronic, structural, and optical modifications. The MIT not only dramatically modifies the VO2 electrical conductivity but also reshapes its anisotropic optical response, making VO2 an exceptional platform for dynamically tunable photonic and optoelectronic devices. In this work, we investigate how the intrinsic crystalline anisotropy of VO2 induces a hyperbolic optical behavior in the metallic rutile phase. We study two epitaxial VO2 thin films of different thicknesses grown on (110) oriented MgF2 substrates. Broadband polarized spectroscopic measurements, spanning the infrared to UV spectral range, are employed to independently investigate the optical response in both the monoclinic and rutile phases. From these measurements, we extract the optical conductivity and the dielectric function, revealing a pronounced anisotropy in the rutile metallic phase, with an enhanced free-carrier response along the rutile c axis. Our data show that, within a narrow near-infrared spectral window, the real parts of the dielectric tensor components along the two principal axes acquire opposite signs, indicating the emergence of a hyperbolic type-II dispersion. The hyperbolic response is quantitatively evaluated through the quality factor and the degree of dielectric anisotropy, enabling a systematic assessment of VO2 as a thermally switchable, hyperbolic optical medium. These findings expand the understanding of anisotropy-driven optical phenomena in phase-change materials and highlight VO2 thin films as a promising platform for tunable and reconfigurable photonic applications.
Fast Programming of In-Plane Hyperbolic Phonon Polariton Optics Through van der Waals Crystals using the Phase-Change Material In3SbTe2
RWTH Aachen University（亚琛工业大学）；Juelich-Aachen Research Alliance (JARA-FIT)（于利希-亚琛研究联盟）；University of Oviedo（奥维耶多大学）；Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo)（纳米材料与纳米技术研究中心，CINN（西班牙国家科研委员会-奥维耶多大学））；Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies（意大利理工学院，生物分子纳米技术中心）
City College of New York（纽约城市学院）；Graduate Center of the City University of New York (CUNY)（纽约市立大学研究生中心）；Universidad Autónoma de Madrid（马德里自治大学）；University of Chemistry and Technology Prague（布拉格化学技术大学）
Topological insulators are tunable waveguides for hyperbolic polaritons
层状拓扑绝缘体，例如Bi $_2$ Se $_3$，在THz频率范围内是光学双曲材料。这种材料具有深度亚衍射，高度定向的集体模式：双曲声子极化激元。在薄晶体中，这种模式的色散被分裂成离散的子带，并受到电子表面态的强烈影响。如果表面态被掺杂，则混合集体模式由声子-极化激元与表面等离子体激元的耦合产生。杂化的强度可以通过改变表面态的化学势的外部门来控制。等离子体-声子耦合的动量依赖性导致了古斯-汉兴效应的极化激元模拟。极化激元射线的方向性及其可调谐的古斯-汉欣位移可以通过太赫兹纳米成像观察到。
Enabling propagation of anisotropic polaritons along forbidden directions via a topological transition
University of Oviedo（奥维耶多大学）；Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo)（纳米材料与纳米技术研究中心，CINN（西班牙国家研究委员会-奥维耶多大学））；Moscow Institute of Physics and Technology（莫斯科物理技术学院）；Institute of Science and Technology Austria（奥地利科学技术研究所）；Donostia International Physics Center (DIPC)（圣塞巴斯蒂安国际物理中心）；IKERBASQUE, Basque Foundation for Science（伊克尔巴斯基克，巴斯克科学基金会）
Spatiotemporal Visualization of Long-Range Anisotropic Plasmon Polaritons in Hyperbolic MoOCl2
The University of Chicago（芝加哥大学）；James Franck Institute, The University of Chicago（詹姆斯·弗兰克研究所，芝加哥大学）；Department of Chemistry, The University of Chicago（化学系，芝加哥大学）；Department of Physics, The University of Chicago（物理系，芝加哥大学）
Ultra-Confinement of Polaritons in Single Atomic Layer Ag Photonic Quantum Dots
The Pennsylvania State University（宾夕法尼亚州立大学）；Joint School of Nanoscience and Nanoengineering, the University of North Carolina at Greensboro（北卡罗来纳大学格林斯伯勒分校纳米科学与工程联合学院）
Room-temperature cavity exciton-polariton condensation in perovskite quantum dots
IBM Research Europe – Zurich（IBM欧洲苏黎世研究中心）；ETH Zurich（苏黎世联邦理工学院）；Institute of Materials Science of Sevilla, Consejo Superior de Investigaciones Científicas − Universidad de Sevilla (CSIC-US)（塞维利亚材料科学研究所，西班牙国家研究委员会-塞维利亚大学）；Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich（苏黎世联邦理工学院化学与应用生物科学学院无机化学实验室）；Empa − Swiss Federal Laboratories for Materials Science and Technology（瑞士联邦材料科学与技术研究院）
Non-Hermitian reconstruction of hybridized hyperbolic shear polaritons
Macao Institute of Materials Science and Engineering (MIMSE), Sino-Luso Joint Laboratory for Optoelectronics, Macau University of Science and Technology（澳门大学科学技术学院澳门科技大学中葡联合光学电子学实验室）；Macau University of Science and Technology Zhuhai MUST Science and Technology Research Institute（澳门科技大学珠海研究院）
Launching of Visible-Range Hyperbolic Polaritons by Gold Nanoantennas in a natural van der Waals crystal
Donostia International Physics Center (DIPC)（多诺西亚国际物理中心）；Department of Physics, University of Oviedo（奥维耶多大学物理系）；Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU)（巴斯克地区大学）；Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC–Universidad de Oviedo)（纳米材料与纳米技术中心，CINN（西班牙国家研究委员会-奥维耶多大学））；IKERBASQUE, Basque Foundation for Science（伊克尔巴斯科奎，巴斯克科学基金会）
Topologically enhanced optical helicity density in the thermal near field of twisted bilayer van der Waals materials
School of Electrical and Computer Engineering, Georgia Institute of Technology（佐治亚理工学院电气与计算机工程学院）；George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology（佐治亚理工学院乔治·W·伍德拉夫机械工程学院）
