Chiral plexcitons, produced by the
strong interaction
between plasmonic
nanocavities and chiral molecules, can provide a promising direction
for controlling chiroptical responses on the nanoscale. Here, we reveal
the chiral origin and electromagnetic hybridization process in chiral
strongly coupled systems. The mechanism and unique advantages of chiral
plexcitons for fine-tuning circular dichroism (CD) responses are demonstrated,
providing a rule for controlling chiral light–matter interactions
in complex chiral nanosystems. Furthermore, we experimentally demonstrate
the fine-tuning of chiral plexcitons in hybrid systems consisting
of plasmonic nanoparticles and chiral J-aggregates. Continuous and
precise tuning of the CD resonance positions was successfully achieved
in a given structure. Compared with the previous work, the CD spectral
tuning accuracy has been improved by an order of magnitude, which
can reach the level of 1 nm. Our findings provide a feasible strategy
and theoretical basis for accurately controlling chirality in multiple
dimensions