Detecting colour on the nanoscale Feb 19, 2009 2 comments
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 very weak 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. Xinjian Zhou and colleagues at
the Sandia National Laboratories in California are taking an
alternative approach, which is similar to the way that retinal
molecules absorb light and then convert the light into
electrical signals. This involves coup