  The interaction of light with subwavelength metallic nano-structures is at
the heart of different current scientific hot topics, namely plasmonics,
metamaterials and nanoantennas. Research in these disciplines during the last
decade has given rise to new, powerful concepts providing an unprecedented
degree of control over light manipulation at the nanoscale. However, only
recently have these concepts been used to increase the capabilities of light
processing in current photonic integrated circuits (PICs), which traditionally
rely only on dielectric materials with element sizes larger than the light
wavelength. Amongst the different PIC platforms, silicon photonics is expected
to become mainstream, since manufacturing using well-established CMOS processes
enables the mass production of low-cost PICs. In this review we discuss the
benefits of introducing recent concepts arisen from the fields of
metamaterials, plasmonics and nanoantennas into a silicon photonics integrated
platform. We review existing works in this direction and discuss how this
hybrid approach can lead to the improvement of current PICs enabling novel and
disruptive applications in photonics.
