Photon in a fibre

RESEARCHERS at the Vienna Centre for Quantum Science and Technology have demonstrated a nanofibre device that acts as an optical diode, allowing single photons to travel in only one direction. This work has been published in “Physical Review X”.

Light-based (photonic) circuits can potentially be faster and consume less power than electronic circuits. Photonic circuits will require many of the same components found in electronics, such as diodes, which allow light or currents to flow in one direction only. In the prototype developed by the researchers, the passage of individual photons through a fibre can be controlled by their interaction with cold atoms trapped in the vicinity of a nanometer-thin optical fibre. Proof-of-principle experiments have revealed a roughly 20-fold difference in the transmission of light moving in the two directions. The scheme can work on single photons, making it suitable for quantum optical networks, which operate at low levels of light.

R. Ramachandran