Thompson, RJ;
Siday, T;
Glass, S;
Luk, TS;
Reno, JL;
Brener, I;
Mitrofanov, O;
(2017)
Optically thin hybrid cavity for terahertz photo-conductive detectors.
Applied Physics Letters
, 110
(4)
10.1063/1.4974482.
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Abstract
The efficiency of photoconductive (PC) devices, including terahertz detectors, is constrained by the bulk optical constants of PC materials. Here, we show that optical absorption in a PC layer can be modified substantially within a hybrid cavity containing nanoantennas and a Distributed Bragg Reflector. We find that a hybrid cavity, consisting of a GaAs PC layer of just 50 nm, can be used to absorb >75% of incident photons by trapping the light within the cavity. We provide an intuitive model, which describes the dependence of the optimum operation wavelength on the cavity thickness. We also find that the nanoantenna size is a critical parameter, small variations of which lead to both wavelength shifting and reduced absorption in the cavity, suggesting that impedance matching is key for achieving efficient absorption in the optically thin hybrid cavities.
| Type: | Article |
|---|---|
| Title: | Optically thin hybrid cavity for terahertz photo-conductive detectors |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1063/1.4974482 |
| Publisher version: | http://dx.doi.org/10.1063/1.4974482 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Science & Technology, Physical Sciences, Physics, Applied, Physics, GAAS, OPTOELECTRONICS, GENERATION, ANTENNAS, DEVICES |
| 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/1558275 |
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