A team of researchers from the United States (U.S.) and Germany created a new optical detector from graphene. This new optical sensor is capable of reacting very quickly to light with varying wavelengths and forms. It also has the ability to work even at room temperature.
The new optical detector created by Helmholtz-Zentrum Dresden-Rossendorf (HZDR) scientists can monitor the incorporeal range of light - from visible to infrared to terahertz radiation. The new graphene detector is made out of a minuscule flake graphene placed on a silicon carbide with an antenna attached. To date, it is the other detector that can cover the monitoring of light from visible to terahertz radiation.
The antenna and the graphene flake act as rays' absorbers, which then transfer the photons' energy to the graphene's electrons. The antenna acts like some sort of funnel that catches long-wave infrared and terahertz radiation. The detector's electrical resistance are increased by the energy of the 'hot electrons'. This activity results in the production of very fast electric signals. The signals are so fast the detector can monitor the light incident in as fast as 40 picoseconds.
"In contrast to other semiconductors like silicon or gallium arsenide, graphene can pick up light with a very large range of photon energies and convert it into electric signals," said Dr. Stephan Winnerl, physicist at HZDR's Institute of Ion Beam Physics and Materials Research. Winnerl added that the team needed only the correct substrate and a broadband antenna to produce the ideal environments.
The antecedent to the new graphene detector was created by the HZDR doctoral student Martin Mittendorff in 2013. Two years later, Mittendorff perfected the prototype together with colleagues in Dresden and a team of scientists from Marburg, Darmstadt and Regensburg in Germany. Mittendorff is working as a postdoctoral researcher at University of Maryland in the U.S.
The construct is already being employed to synchronize two laser systems at the ELBE Center in Germany. One major advantage of the new graphene detector is that it functions in room temperature. Unlike other detectors, it cuts out the requirement for costly and time-consuming helium or nitrogen cooling methods.
The study titled "Universal ultrafast detector for short optical pulses based on graphene" was published their study in Optics Express on Oct. 23, 2015.