[1]https://en.wikipedia.org/wiki/Visible_light_communication
   In telecommunications, visible light communication (VLC) is the use of
   visible light (light with a frequency of 400–800 THz/wavelength of
   780–375 nm) as a transmission medium. VLC is a subset of optical
   wireless communications technologies.

References

   1. https://en.wikipedia.org/wiki/Visible_light_communication