Journal
ACS PHOTONICS
Volume 8, Issue 3, Pages 771-780Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acsphotonics.0c01194
Keywords
Bi2Se3; terahertz; metasurfaces; topological insulators; ultrafast photoswitching; carrier dynamics
Categories
Funding
- National Natural Science Foundation (NSF) of China [11802339, 11805276, 61805282, 61801498, 11804387, 11902358]
- Scientific Researches Foundation of National University of Defense Technology [ZK16-03-59, ZK18-01-03, ZK18-03-36, ZK18-03-22]
- NSF of the Hunan province [2016JJ1021]
- Hunan Provincial Innovation Foundation for Postgraduate [CX2018B006]
- Open Research Fund of Hunan Provincial Key Laboratory of High Energy Technology [GNJGJS03]
- Opening Foundation of State Key Laboratory of Laser Interaction with Matter [SKLLIM1702]
- Youth Talent Lifting Project [17-JCJQ-QT-004]
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This study presents a comprehensive investigation on the active photonic performance of a novel metaphotonic device by hybridizing ultrathin Bi2Se3 bridges into metamaterials in the THz range. The results show remarkable electromagnetically induced transparency transmission and group delay modulations, with the modulation depth reaching up to 31% and 2.7 ps, respectively, at the operational frequency. The ultrafast switching speed up to a hundred GHz is achieved due to the short photocarrier lifetime in Bi2Se3 films.
Because of the wealth of fascinating physical phenomena observed in topological insulators (TIs), their exciting properties have been intensively investigated for electronic and optoelectronic applications, such as quantum devices, saturable absorbers, and photodetectors, in the visible to terahertz (THz) spectral range. However, their potential for metaphotonic devices has yet to be explored. Here, we present a comprehensive investigation on the active photonic performance of a novel metaphotonic device by hybridizing ultrathin Bi2Se3 bridges into metamaterials in the THz range. Unlike THz modulation via Fano-like plasmon-phonon destructive interference in the pure Bi2Se3 structure, our Bi2Se3 microribbon arrays with high photo-conductivity can short-circuit the circulating surface currents in the proposed metasurfaces, leading to remarkable electromagnetically induced transparency (EIT) transmission and group delay modulations at the operational frequency. Additionally, the width of the Bi2Se3 bridges is optimized to 20 mu m to maximize the modulation depth, with the modulation of the transmission resonance amplitude and the group delay as high as 31% and 2.7 ps, respectively. Due to the short photocarrier lifetime in Bi2Se3 films (within a few picoseconds), the full recovery time after photoinjection is less than 9.5 ps, enabling an ultrafast switching speed up to a hundred GHz. The ultrafast and effective control of the light spectrum in Bi2Se3-functionalized metaphotonic systems lays the foundation for promoting the emergence of TI-based optoelectronics.
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