Long-range hyperbolic polaritons on a non-hyperbolic crystal surface

• 成果类型: Article
• 署名作者: Liu, Lu; Xiong, Langlang; Wang, Chongwu; Bai, Yihua; Ma, Weiliang; Wang, Yupeng; Li, Peining; Li, Guogang; Wang, Qi Jie; Garcia-Vidal, Francisco J.; Dai, Zhigao; Hu, Guangwei
• 署名单位: China University of Geosciences; Nanyang Technological University; University of Electronic Science & Technology of China; Huazhong University of Science & Technology; Huazhong University of Science & Technology; China University of Geosciences; Autonomous University of Madrid; Autonomous University of Madrid; China University of Geosciences; Nanyang Technological University
• 刊物名称: Nature
• ISSN/ISSBN: 0028-1670
• DOI: 10.1038/s41586-025-09288-1
• 发表日期: 2025-08-07
• 关键词: negative refraction

摘要

Hybridized matter-photon excitations in hyperbolic crystals-anisotropic materials characterized by permittivity tensor components with opposite sign-have attracted substantial attention owing to their strong light-matter interactions in the form of hyperbolic polaritons1, 2-3. However, these phenomena have been restricted to hyperbolic crystals, whose optical responses are confined to fixed spectral regions and lack tunability, thereby limiting their broader applicability4,5. Here we demonstrate the emergence of hyperbolic surface phonon polaritons in a non-hyperbolic yttrium vanadate (YVO4) crystal. Using real-space nanoimaging combined with theoretical analyses, we visualize hyperbolic wavefronts of surface phonon polaritons on YVO4 crystal surfaces within its non-hyperbolic frequency range, where the permittivity tensor components of the material have the same negative sign. Furthermore, by varying the temperature from room temperature to cryogenic levels, we realize in situ manipulation of polariton dispersions, enabling a topological transition from hyperbolic to canalization and eventually to the elliptic regime. This temperature-controlled dispersion engineering not only provides precise control over polariton topology but also modulates their wavelength and group velocity, showing remarkable sensitivity alongside low-loss, long-range propagation. These findings extend the realm of hyperbolic nano-optics by removing the reliance on hyperbolic crystals, unlocking opportunities for applications in negative refraction6, 7, 8, 9-10, superlensing11,12, polaritonic chemistry13, integrated photonics14, 15-16 and beyond.