Gate-tunable negative refraction of mid-infrared polaritons

• 成果类型: Article
• 署名作者: Hu, Hai; Chen, Na; Teng, Hanchao; Yu, Renwen; Xue, Mengfei; Chen, Ke; Xiao, Yuchuan; Qu, Yunpeng; Hu, Debo; Chen, Jianing; Sun, Zhipei; Li, Peining; Garcia de Abajo, F. Javier; Dai, Qing
• 署名单位: Chinese Academy of Sciences; National Center for Nanoscience & Technology, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Stanford University; Barcelona Institute of Science & Technology; Universitat Politecnica de Catalunya; Institut de Ciencies Fotoniques (ICFO); ICREA; Chinese Academy of Sciences; Institute of Physics, CAS; Aalto University; Huazhong University of Science & Technology; Huazhong University of Science & Technology
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-14127
• DOI: 10.1126/science.adf1251
• 发表日期: 2023-02-10
• 页码: 558-+
• 关键词: graphene plasmons; phonon polaritons; optics; metamaterials

摘要

Negative refraction provides a platform to manipulate mid-infrared and terahertz radiation for molecular sensing and thermal emission applications. However, its implementation based on metamaterials and plasmonic media presents challenges with optical losses, limited spatial confinement, and lack of active tunability in this spectral range. We demonstrate gate-tunable negative refraction at mid-infrared frequencies using hybrid topological polaritons in van der Waals heterostructures. Specifically, we visualize wide-angle negatively refracted polaritons in a-MoO3 films partially decorated with graphene, undergoing reversible planar nanoscale focusing. Our atomically thick heterostructures weaken scattering losses at the interface while enabling an actively tunable transition of normal to negative refraction through electrical gating. We propose polaritonic negative refraction as a promising platform for infrared applications such as electrically tunable super-resolution imaging, nanoscale thermal manipulation, enhanced molecular sensing, and on-chip optical circuitry.