We explore by theoretical means an extreme renormalisation of the
eigenmodes of a dimer of dipolar meta-atoms due to strong light-matter interactions.
Firstly, by tuning the height of an enclosing photonic cavity, we can lower the energy
level of the symmetric ‘bright’ mode underneath that of the anti-symmetric ‘dark’
mode. This ...
We explore by theoretical means an extreme renormalisation of the
eigenmodes of a dimer of dipolar meta-atoms due to strong light-matter interactions.
Firstly, by tuning the height of an enclosing photonic cavity, we can lower the energy
level of the symmetric ‘bright’ mode underneath that of the anti-symmetric ‘dark’
mode. This is possible due to the polaritonic nature of the symmetric mode, that
shares simultaneously its excitation with the cavity and the dimer. For a heterogeneous
dimer, we show that the polariton modes can be smoothly tuned from symmetric to
anti-symmetric, resulting in a variable mode localisation from extended throughout
the cavity to concentrated around the vicinity of the dimer. In addition, we reveal
a critical point where one of the meta-atoms becomes ‘shrouded’, with no response
to a driving electric field, and thus the field re-radiated by the dimer is only that of
the other meta-atom. We provide an exact analytical description of the system from
first principles, as well as full-wave electromagnetic simulations that show a strong
quantitative agreement with the analytical model. Our description is relevant for any
such physical dimer where dipolar interactions are the dominant mechanism.
