University of Maryland researchers have developed a new light detector that is capable of seeing light wavelengths that are invisible to the human eye. Most detectors need to be kept extremely cold to maintain sensitivity, but this new detector is used at room temperature due to the use of graphene. Special properties in graphene have allowed the researchers to increase the detection speed and also maintain sensitivity in the terahertz range.
A new technique called “hot-electron photothermoelectric effect” allows light to be absorbed by electrons in graphene, and then the electrons escape through electrical leads. Two different types of metals are used for the leads and because of their conductivity differences, an electrical signal is produced. The electrical signal detects terahertz waves beneath the surface of bodies, walls, and other objects.