Tailoring the photon hopping by nearest-neighbor and next-nearest-neighbor interaction in photonic arrays

Arrays of photonic cavities are relevant structures for developing large-scale photonic integrated circuits and for investigating basic quantum electrodynamics phenomena due to the photon hopping between interacting nanoresonators. Here we investigate, by means of scanning near-field spectroscopy, numerical calculations and an analytical model, the role of different neighboring interactions that give rise to delocalized supermodes in different photonic crystal array configurations. The systems under investigation consist of three nominally identical two-dimensional photonic crystal nanocavities on membrane aligned along the two symmetry axes of the triangular photonic crystal lattice. We find that the nearest-neighbor and next-nearest-neighbor coupling terms can be of the same relevance. In this case, a nonintuitive picture describes the resonant modes, and the photon hopping between adjacent nanoresonators is strongly affected. Our findings prove that exotic configurations and even postfabrication engineering of coupled nanoresonators could directly tailor the mode spatial distribution and the group velocity in coupled resonator optical waveguides.