Mid-infrared analogue polaritonic reversed Cherenkov radiation in natural anisotropic crystals.

ABSTRACT: Cherenkov radiation (CR) excited by fast charges can serve as on-chip light sources with a nanoscale footprint and broad frequency range. The reversed CR, which usually occurs in media with the negative refractive index or negative group-velocity dispersion, is highly desired because it can effectively separate the radiated light from fast charges thanks to the obtuse radiation angle. However, reversed CR at the mid-infrared remains challenging due to the significant loss of conventional artificial structures. Here we observe mid-infrared analogue polaritonic reversed CR in a natural van der Waals (vdW) material (i.e., α-MoO₃), whose hyperbolic phonon polaritons exhibit negative group velocity. Further, the real-space image results of analogue polaritonic reversed CR indicate th

SUBMITTER: Guo X 

PROVIDER: S-EPMC10156754 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature