Ultralarge Rabi splitting and broadband strong coupling in a spherical hyperbolic metamaterial cavity

Strong coupling (SC) between two resonant plasmon modes can result in the formation of new hybrid modes exhibiting Rabi splitting with strong energy exchange at the nanoscale. However, normal Rabi splitting is often limited to similar to 50-320 meV due to the short lifetime of the plasmon mode. Here, we theoretically demonstrate a record Rabi splitting energy as large as 805 meV arising from the SC between the high-Q plasmonic whispering gallery mode and high-Q cavity plasmon resonance supported by a spherical hyperbolic metamaterial cavity, which consists of a dielectric nanosphere core wrapped in 7 alternating layers of silver/dielectric materials. In addition, the new hybrid modes formed by the SC are shown to exhibit an extralong lifetime of up to 71.9-81.6 fs, with the large electric field intensity enhancement at both the dielectric core and the dielectric layers. More importantly, the spectral ranges of SC can be tuned across an ultrabroad range from the visible to the near-IR by simply changing the dielectric core size. These findings may have potential applications in bright single-photon sources. (C) 2021 Chinese Laser Press

Automated summary

Strong coupling between high-Q plasmonic whispering gallery mode and high-Q cavity plasmon resonance can lead to a record Rabi splitting energy of 805 meV, with new hybrid modes exhibiting an extralong lifetime and large electric field intensity enhancement. These findings may have potential applications in bright single-photon sources.