  We investigate a class of multilayered metamaterials characterized by
moderate-index inclusions and low average permittivity. Via first-principle
calculations, we show that in such scenario first- and second-order spatial
dispersion effects may exhibit a dramatic and non-resonant enhancement, and may
become comparable to the local response. Their interplay gives access to a
wealth of dispersion regimes encompassing additional extraordinary waves and
topological phase transitions. In particular, we identify a novel configuration
featuring bound and disconnected isofrequency contours. Since they do not rely
on high-index inclusions, our proposed metamaterials may constitute an
attractive and technologically viable platform for engineering nonlocal effects
in the optical range.
