Multilayered van der Waals (vdW) materials are semiconductors composed of atomically thin crystal layers

held together by weak vdW forces. They offer unique crystal structures and electronic properties

distinct from conventional semiconductors

making them a promising platform for linear and nonlinear optics. In this context

the large refractive indexes given by highly polarizable transition metals

combined with excitonic resonances and unconventional crystalline structures

provides a toolbox for exploring non-linear physics and strong light–matter interactions with unprecedented opportunities for nanoscale optics. Recent reports highlight novel vdW materials

particularly PdPSe

a pentagonal crystal with strong nonlinear responses

and As

2

S

3

a record high birefringence crystal

as favorable candidates to engineer nonlinear responses and miniaturization of optical components

owing to the combination of high refractive index and strong optical anisotropy of the underlying crystal structures. While still in its infancy

rese

arch on vdW materials promise a florid ground for fundamental studies

bridging the gap between material science and nanoscale optics.