Mitrofanov, O;
(2019)
Terahertz Detection with Perfectly-Absorbing Photoconductive Metasurface.
[Letter].
Nano Letters
, 19
(5)
pp. 2888-2896.
10.1021/acs.nanolett.8b05118.
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Abstract
Terahertz (THz) photoconductive devices are used for generation, detection, and modulation of THz waves, and they rely on the ability to switch electrical conductivity on a subpicosecond time scale using optical pulses. However, fast and efficient conductivity switching with high contrast has been a challenge, because the majority of photoexcited charge carriers in the switch do not contribute to the photocurrent due to fast recombination. Here, we improve efficiency of electrical conductivity switching using a network of electrically connected nanoscale GaAs resonators, which form a perfectly absorbing photoconductive metasurface. We achieve perfect absorption without incorporating metallic elements, by breaking the symmetry of cubic Mie resonators. As a result, the metasurface can be switched between conductive and resistive states with extremely high contrast using an unprecedentedly low level of optical excitation. We integrate this metasurface with a THz antenna to produce an efficient photoconductive THz detector. The perfectly absorbing photoconductive metasurface opens paths for developing a wide range of efficient optoelectronic devices, where required optical and electronic properties are achieved through nanostructuring the resonator network.
| Type: | Article |
|---|---|
| Title: | Terahertz Detection with Perfectly-Absorbing Photoconductive Metasurface |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1021/acs.nanolett.8b05118 |
| Publisher version: | https://doi.org/10.1021/acs.nanolett.8b05118 |
| 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: | Metasurface; perfect absorption; photoconductive detector; Terahertz |
| 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/10072927 |
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