Anapole assisted self-hybridized exciton-polaritons in perovskite metasurfaces.

The exciton-polaritons in a lead halide perovskite not only have great significance for macroscopic quantum effects but also possess vital potential for applications in ultralow-threshold polariton lasers, integrated photonics, slow-light devices, and quantum light sources. In this study, we have successfully demonstrated strong coupling with huge Rabi splitting of 553 meV between perovskite excitons and anapole modes in the perovskite metasurface at room temperature. This outcome is achieved by introducing anapole modes to suppress radiative losses, thereby confining light to the perovskite metasurface and subsequently hybridizing it with excitons in the same material. Our results indicate the formation of self-hybridized exciton-polaritons within the perovskite metasurface, which may pave the way towards achieving high coupling strengths that could potentially bring exciting phenomena to fruition, such as Bose-Einstein condensation as well as enabling applications such as efficient light-emitting diodes and lasers.

Group Velocity Modulation and Light Field Focusing of the Edge States in Chirped Valley Graphene Plasmonic Metamaterials.

The valley degree of freedom, like the spin degree of freedom in spintronics, is regarded as a new information carrier, promoting the emerging valley photonics. Although there exist topologically protected valley edge states which are immune to optical backscattering caused by defects and sharp edges at the inverse valley Hall phase interfaces composed of ordinary optical dielectric materials, the dispersion and the frequency range of the edge states cannot be tuned once the geometrical parameters of the materials are determined. In this paper, we propose a chirped valley graphene plasmonic metamaterial waveguide composed of the valley graphene plasmonic metamaterials (VGPMs) with regularly varying chemical potentials while keeping the geometrical parameters constant. Due to the excellent tunability of graphene, the proposed waveguide supports group velocity modulation and zero group velocity of the edge states, where the light field of different frequencies focuses at different specific locations. The proposed structures may find significant applications in the fields of slow light, micro-nano-optics, topological plasmonics, and on-chip light manipulation.