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A detector made from graphene in future telescopes could greatly supercharge their abilities to reveal more of the hidden universe.
Researchers from Chalmers University of Technology in Sweden have discovered that along with its many other potential uses in gadgets and batteries, graphene could also revolutionise the potential of next-generation telescopes.
Until now – beyond superconductors – there were few materials capable of making ultra-sensitive and fast terahertz (THz) detectors for astronomy. However, writing in Nature Astronomy, the researchers showed that engineered graphene adds a new material paradigm for THz heterodyne detection.
Crucial to the breakthrough was graphene’s ability to be an excellent conductor without having any electrons present. As part of this study, the researchers achieved a near zero-electron scenario – also referred to as the Dirac point – by assembling electron-accepting molecules on its surface.
In experiments, the graphene combined two different signals as part of heterodyne detection. The first being a high-intensity wave known as THz frequency generated by a local oscillator, and the second being a faint THz signal that mimics waves from deep space.
‘Enormous potential for future space missions’
The graphene mixes these signals to produce an output wave at a much lower gigahertz (GHz) frequency, which can be analysed with standard low-noise gigahertz electronics. The higher this frequency can be, the higher bandwidth the detector can have to accurately identify motions inside the celestial objects.
“According to our theoretical model, this graphene THz detector has a potential to reach quantum-limited operation for the important 1-5THz spectral range,” said co-author of the paper, Sergey Cherednichenko.
“Moreover, the bandwidth can exceed 20GHz, larger than 5GHz that the state-of-the-art technology has to offer.”
Also in this new detector’s favour is the extremely low power needed for the local oscillator to achieve a trustable detection of faint THz signals. This could enable quantum-limited THz coherent detector arrays, hence opening the door to 3D imaging of the universe.
Elvire De Beck of the university’s Department of Space, Earth and Environment, who was not involved in this research, said the breakthrough has enormous potential.
“This graphene-based technology has enormous potential for future space missions that aim at unveiling how water, carbon, oxygen and life itself came to Earth,” she said.
