Observation of naturally canalized phonon polaritons in LiV2O5 thin layers

作者：Ana I. F. Tresguerres‐Mata, C. Lanza, Javier Taboada‐Gutiérrez, Joseph R. Matson, Gonzalo Álvarez‐Pérez, Masahiko Isobe, Aitana Tarazaga Martín-Luengo, Jiahua Duan, Stefan Partel, M. Vélez, Javier Martín‐Sánchez, Alexey Y. Nikitin, Joshua D. Caldwell, Pablo Alonso‐González · 发表于：Nature Communications · 年份：2024 · DOI：10.1038/s41467-024-46935-z · 被引用次数：31 · 研究领域：Plasmonic and Surface Plasmon Research、Metamaterials and Metasurfaces Applications、Photonic and Optical Devices

Abstract Polariton canalization is characterized by intrinsic collimation of energy flow along a single crystalline axis. This optical phenomenon has been experimentally demonstrated at the nanoscale by stacking and twisting van der Waals (vdW) layers of α-MoO 3 , by combining α-MoO 3 and graphene, or by fabricating an h-BN metasurface. However, these material platforms have significant drawbacks, such as complex fabrication and high optical losses in the case of metasurfaces. Ideally, it would be possible to canalize polaritons “naturally” in a single pristine layer. Here, we theoretically predict and experimentally demonstrate naturally canalized phonon polaritons (PhPs) in a single thin layer of the vdW crystal LiV 2 O 5 . In addition to canalization, PhPs in LiV 2 O 5 exhibit strong field confinement ( $${{{{{{\boldsymbol{\lambda }}}}}}}_{{{{{{\bf{p}}}}}}} \sim \frac{{{{{{{\boldsymbol{\lambda }}}}}}}_{{{{{{\bf{0}}}}}}}}{{{{{{\bf{27}}}}}}}$$ λ p ~ λ 0 27 ), slow group velocity (0.0015c), and ultra-low losses (lifetimes of 2 ps). Our findings are promising for the implementation of low-loss optical nanodevices where strongly directional light propagation is needed, such as waveguides or optical routers.