Jung, Hyunseung;
Hale, Lucy L;
Briscoe, Jayson;
Sarma, Raktim;
Luk, Ting Shan;
Addamane, Sadhvikas J;
Reno, John L;
... Mitrofanov, Oleg; + view all
(2022)
Terahertz Detection Using Enhanced Two-Step Absorption in Photoconductive Metasurfaces Gated at lambda=1.55 mu m.
Advanced Optical Materials
, Article 2201838. 10.1002/adom.202201838.
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Revised Manuscript_AdOM_1550 nm GaAs MS_HJung_LH_preprint.pdf - Accepted Version Access restricted to UCL open access staff until 31 October 2023. Download (1MB) |
Abstract
Superior ultrafast photoconductive properties make low temperature grown (LT) GaAs one of the best materials for photoconductive terahertz (THz) detection. However, the large bandgap of LT-GaAs limits its operation to gating at wavelengths shorter than 870 nm. Here, it is demonstrated for the first time that nanostructuring the LT-GaAs into a highly absorbing metasurface enables THz photoconductive detection with a pulsed laser at λ = 1.55 µm. The very weak sub-bandgap absorption mediated by midgap states in LT-GaAs is strongly enhanced using the concept of perfect absorption via degenerate critical coupling. Integrated with a THz antenna, the LT-GaAs metasurface enables high sensitivity THz detection with a high dynamic range of 60 dB and large bandwidth up to 4.5 THz. The LT-GaAs metasurface has the potential to serve as a universal ultrafast switching element for THz applications, enabling low-cost, turn-key THz systems for a variety of real-world applications.
Type: | Article |
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Title: | Terahertz Detection Using Enhanced Two-Step Absorption in Photoconductive Metasurfaces Gated at lambda=1.55 mu m |
DOI: | 10.1002/adom.202201838 |
Publisher version: | https://doi.org/10.1002/adom.202201838 |
Language: | English |
Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
Keywords: | ANTENNAS, GENERATION, Materials Science, Materials Science, Multidisciplinary, metasurfaces, nanofabrication, Optics, photoconductive antenna, Physical Sciences, POWER, RADIATION, Science & Technology, spectroscopy, Technology, terahertz detection, THZ |
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/10160554 |
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