Scientists say graphene allows control of light emission

1 min read

Lasers, displays and other light emitting depend upon the electrically controlled modulation of photons. But, says a research team, electrical control of the light emission pathways opens up the possibility of novel types of nano photonics devices, based on active plasmonics.

Scientists from ICFO, MIT, CNRS, CNISM and Graphenea have demonstrated active electrical control of the energy flow from erbium ions into photons and plasmons. The experiment was implemented by placing the erbium emitters a few nanometres from a graphene sheet, whose carrier density – or Fermi energy – is controlled electrically.

Erbium ions emit light at a wavelength of 1.5µm – the third telecom window. This is important for optical telecommunications because there is little energy loss in this range, and so data transmission is highly efficient.

The team has shown that the energy flow from erbium into photons or plasmons can be controlled simply by applying a small electrical voltage. As the Fermi energy of the graphene sheet was increased, the erbium emitters went from exciting electrons in the graphene sheet to emitting photons or plasmons. The experiments revealed graphene plasmons at near infrared frequencies, relevant for these telecommunications applications. In addition, the strong concentration of optical energy is said to offer potential for data storage and manipulation through active plasmonic networks.