  The integration of two-dimensional (2D) materials with photonic structures
has catalyzed a wide spectrum of optical and optoelectronic applications.
Conventional nanophotonic structures generally lack efficient reconfigurability
and multifunctionality. The atomically thin 2D van der Waals materials can thus
infuse new functionality and reconfigurability to the well-established library
of photonic structures such as integrated waveguides, optical fibers, photonic
crystals, micro-cavities, and metasurface, to name a few. Thanks to the
handiness of van der Waals interfaces, the 2D materials can be easily
transferred and mixed with other prefabricated photonic templates with high
degrees of freedom, and can act as the optical gain, modulation, sensing, or
plasmonic media for diverse applications. Here we review recent advents on
combining 2D materials to nanophotonic structures for new functionality
development or performance enhancements. Challenges and emerging opportunities
in integrating van der Waals building blocks beyond 2D materials are also
discussed.
