  Near-zero-index platforms arise as a new opportunity for light manipulation
with boosting of optical nonlinearities, transmission properties in waveguides
and constant phase distribution. In addition, they represent a solution to
impedance mismatch faced in photonic circuitry offering several applications in
quantum photonics, communication and sensing. However, their realization is
limited to availability of materials that could exhibit such low-index. For
materials used in the visible and near-infrared wavelengths, the intrinsic
losses annihilate most of near-zero index properties. The design of
all-dielectric photonic crystals with specific electromagnetic modes overcame
the issue of intrinsic losses while showing effective mode index near-zero.
Nonetheless, these modes strongly radiate to the surrounding environment,
greatly limiting the devices applications. Here, we explore a novel
all-dielectric photonic crystal structure that is able to sustain effective
near-zero-index modes coupled to directive bound-states in the continuum in
order to decrease radiative losses, opening extraordinary opportunities for
radiation manipulation in nanophotonic circuits. Moreover, its relatively
simple design and phase stability facilitates integration and reproducibility
with other photonic components.
