The new development comes from Chalmers University of Technology and it considers future breakthroughs in detector technology, which is the basis for improving space telescopes in general. To advance image resolution further, the researchers state that new concepts of terahertz (THz) coherent receivers are required. Such receivers can provide larger bandwidths and imaging capabilities with multipixel focal plane heterodyne arrays.
The key to achieving this is graphene. The material has been shown to enable highly sensitive and wideband coherent detection of signals from 90 to 700 GHz and, this could extend across the entire terahertz range. Graphene is an allotrope of carbon in the form of a single layer of atoms in a two-dimensional hexagonal lattice. The material is light, transparent, strong, and highly-conductive. Graphene is the basis of many advances, both current and potential, with an array of optical and electronic devices.
Because grapheme can achieve a near zero-electron scenario (the Dirac point), this provides the key to moving telescopes to the next stage. The researchers demonstrated that by assembling electron-accepting molecules on the surface of graphene, it functions as an exceptional material for THz heterodyne detection when it is doped to the Dirac point.
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Using graphene the reseat hers have tested out a lightweight, power effective 3D imager which is quantum-limited at terahertz frequencies.
According to one of the researchers, Professor Sergey Cherednichenko: “According to our theoretical model, this graphene THz detector has a potential to reach quantum-limited operation for the important 1-5 THz spectral range. Moreover, the bandwidth can exceed 20 GHz, larger than 5 GHz that the state of the artstate-of-the-art technology has to offer.”
The following video provides an experimental demonstration of THz wave detection with charge-neutral epitaxial graphene, conducted by the researchers:
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The research has been published in the journal Nature Astronomy, with the research paper titled “Towards quantum-limited coherent detection of terahertz waves in charge-neutral graphene.”
