Efficient generation of photon pairs from modified carbon nanotubes

Truly secure communications. No eavesdropping. That's the promise of quantum communication. One challenge to making it a reality is light. We need an efficient way to create packets of light, called photons. Now, scientists have identified how modified carbon nanotubes emit photon pairs. The experiments and theory show that the photon pairs are the result of the capture and recombination of two excitons (electron–hole pairs). The evidence suggests that this is an efficient process for generating photon pairs.

The team's research shows how to produce photons efficiently using tiny tubes of carbon. Such production could lead to ultra-secure ways to pass messages (quantum communications). The approach could also change lasers, used in everything from consumer electronics to scientific instruments. Of additional appeal is that modifying the carbon nanotubes involves a simple deposition of silicon or aluminum oxide thin films. This makes the tubes compatible with existing microelectronic technologies. It also opens a path to develop photonic integrated circuits.