Scientists in the US have copied the way the retina sends electrical signals to the brain in order to construct nanoscale colour detectors. The devices, composed of carbon nanotubes decorated with photosensitive molecules, can detect very weak sources of visible light at specific wavelengths and could have applications in astronomy and biology.

The ability to detect photons over just a few square nanometres is useful in studying light sources that are either veryweak or very small. To date, researchers have attempted this largely through the construction of solid-state devices, which produce electron-hole pairs when illuminated. However, building such devices with nanoscale precision is extremely difficult.

If you want to continue reading this article at Optics, click here.