  Large optical anisotropy observed in a broad spectral range is of paramount
importance for efficient light manipulation in countless devices. Although a
giant anisotropy was recently observed in the mid-infrared wavelength range,
for visible and near-infrared spectral intervals, the problem remains acute
with the highest reported birefringence values of 0.8 in BaTiS3 and h-BN
crystals. This inspired an intensive search for giant optical anisotropy among
natural and artificial materials. Here, we demonstrate that layered transition
metal dichalcogenides (TMDCs) provide an answer to this quest owing to their
fundamental differences between intralayer strong covalent bonding and weak
interlayer van der Walls interaction. To do this, we carried out a correlative
far- and near-field characterization validated by first-principle calculations
that reveals an unprecedented birefringence of 1.5 in the infrared and 3 in the
visible light for MoS2. Our findings demonstrate that this outstanding
anisotropy allows for tackling the diffraction limit enabling an avenue for
on-chip next-generation photonics.
