Seddon, James;
Hale, Lucy;
Jung, Hyunseung;
Norman, Sarah;
Brener, Igal;
Seeds, Alwyn;
Renaud, Cyril;
(2024)
Continuous wave terahertz detection using 1550 nm pumped nonlinear photoconductive GaAs metasurfaces.
Optics Express
, 32
(6)
pp. 9809-9819.
10.1364/OE.517422.
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Abstract
Terahertz (THz) continuous wave (CW) spectroscopy systems can offer extremely high spectral resolution over the THz band by photo-mixing high-performance telecommunications-band (1530-1565 nm) lasers. However, typical THz CW detectors in these systems use narrow band-gap photoconductors, which require elaborate material growth and generate relatively large detector noise. Here we demonstrate that two-step photon absorption in a nano-structured low-temperature grown GaAs (LT-GaAs) metasurface which enables switching of photoconductivity within approximately one picosecond. We show that LT-GaAs can be used as an ultrafast photoconductor in CW THz detectors despite having a bandgap twice as large as the telecommunications laser photon energy. The metasurface design harnesses Mie modes in LT GaAs resonators, whereas metallic electrodes of THz detectors can be designed to support an additional photonic mode, which further increases photoconductivity at a desired wavelength.
| Type: | Article |
|---|---|
| Title: | Continuous wave terahertz detection using 1550 nm pumped nonlinear photoconductive GaAs metasurfaces |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1364/OE.517422 |
| Publisher version: | https://doi.org/10.1364/OE.517422 |
| Language: | English |
| Additional information: | © The Author(s), 2024. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. https://creativecommons.org/licenses/by/4.0/ |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10189665 |
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