Resonance coupling between chiral quasi-BICs and achiral molecular excitons in dielectric metasurface J-aggregate heterostructures

The realization of flexible tuning and enhanced chiral responses is vital for many applications in nanophotonics. This study proposes to manipulate the collective optical responses with heterostructures consisting of chiral dielec-tric metasurfaces and achiral J-aggregates. Owing to the resonance coupling between the chiral quasi-bound states in the continuum (QBICs) and the achiral exciton mode, large mode splitting and anticrossing are observed in both the transmission and circular dichroism (CD) spectra, which indicates the formation of hybrid chiral eigenmodes and the realization of the strong coupling regime. Considering that the radiative and dissipative damping of the hybrid eigen-modes depends on the coherent energy exchange, the chiral resonances can be flexibly tuned by adjusting the geome-try and optical constants for the heterostructure, and the CD of the three hybrid eigenmodes approach the maximum (similar to 1) simultaneously when the critical coupling conditions are satisfied, which can be promising for enhanced chiral light-matter interactions. (c) 2023 Optica Publishing Group

Automated summary

The realization of flexible tuning and enhanced chiral responses is vital for many applications in nanophotonics. This study proposes using heterostructures consisting of chiral dielectric metasurfaces and achiral J-aggregates to manipulate the collective optical responses, achieving flexible tuning and enhanced chiral responses. The resonance coupling between the chiral quasi-bound states in the continuum (QBICs) and the achiral exciton mode leads to large mode splitting and anticrossing in both the transmission and circular dichroism (CD) spectra, indicating the formation of hybrid chiral eigenmodes and the realization of the strong coupling regime. Considering that the radiative and dissipative damping of the hybrid eigenmodes depends on the coherent energy exchange, the chiral resonances can be flexibly tuned by adjusting the geometry and optical constants for the heterostructure, and the CD of the three hybrid eigenmodes approach the maximum (similar to 1) simultaneously when the critical coupling conditions are satisfied, which can be promising for enhanced chiral light-matter interactions.