Hu, Y;
You, J;
Tong, M;
Zheng, X;
Xu, Z;
Cheng, X;
Jiang, T;
(2020)
Pump-Color Selective Control of Ultrafast All-Optical Switching Dynamics in Metaphotonic Devices.
Advanced Science
10.1002/advs.202000799.
(In press).
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Abstract
Incorporating active materials into metamaterials is expected to yield exciting advancements in the unprecedented versatility of dynamically controlling optical properties, which sheds new light on the future optoelectronics. The exploration of emerging semiconductors into terahertz (THz) meta-atoms potentially allows achieving ultrafast nanodevices driven by various applications, such as biomedical sensing/imaging, ultrawide-band communications and security scanners. However, ultrafast optical switching of THz radiation is currently limited to a single level of tuning speed, which is a main hurdle to achieve multifunctionalities. Here, a hybrid metadevice which can realize the pump-wavelength controlled ultrafast switching response by the functionalization of double photoactive layers is demonstrated experimentally. A whole cycle of electromagnetically induced transparency switching with a half-recovery state changes from 0.78 ns to 8.8 ps as pump wavelength varies from near infrared to near ultraviolet regions. The observed pump-color selective switching speed changing from nanosecond scale to picosecond scale is ascribed to the wavelength-dependent penetration length of Ge and the contrasting defect states between noncrystalline Ge and epitaxial Si layers. It is believed that the schemes regarding pump-color controllable ultrafast switching behavior introduced here can inspire more innovations across the field of ultrafast photonics and can boost the reconfigurable metamaterial applications.
| Type: | Article |
|---|---|
| Title: | Pump-Color Selective Control of Ultrafast All-Optical Switching Dynamics in Metaphotonic Devices |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/advs.202000799 |
| Publisher version: | http://dx.doi.org/10.1002/advs.202000799 |
| Language: | English |
| Additional information: | © 2020 The Authors. Published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | electromagnetically induced transparency, germanium, silicon, terahertz metamaterials, ultrafast photoswitching, |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Education UCL > Provost and Vice Provost Offices > School of Education > UCL Institute of Education UCL > Provost and Vice Provost Offices > School of Education > UCL Institute of Education > Centre for Languages and Intl Educatn |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10105165 |
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