  Light can be used for wireless information transmission apart from
illumination; that is the key idea behind visible-light communication (VLC),
one of the disruptive technologies of our days. It combines remarkably high
data rates due to ultrashort wavelengths with huge reliability and security due
to small distances; nevertheless, it substantially suffers from interference of
neighboring light sources in multiple-link configurations. In this manuscript,
we investigate a pair of light emitting diodes (LEDs) interfering each other
and propose a simple nanoslit metasurface that radically increases the
directivity of the transmitting beams. As a result, enhancement of the
signal-to-interference ratio by several orders of magnitude is reported. The
considered generic setup retains its beneficial features in the presence of
realistic design defects and, accordingly, may inspire standardization efforts
towards the adoption of VLC in next-generation heterogeneous communication
networks.
