Gate-controlled terahertz focusing based on graphene-loaded metasurface

Metasurfaces have proven their great application potentials in terahertz (THz) wave modulations. However, realizing an active metasurface retaining lensing functionality in the THz frequency regime is still highly desired. Here a metalens, featuring electrically tunable focal length, based on propag...

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Bibliographic Details
Published in:Optics express 2020-02, Vol.28 (3), p.2789-2798
Main Authors: Ullah, Naeem, Liu, Weiguang, Wang, Guocui, Wang, Zongyuan, Khalid, Ata Ur Rahman, Hu, Bin, Liu, Juan, Zhang, Yan
Format: Article
Language:English
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Summary:Metasurfaces have proven their great application potentials in terahertz (THz) wave modulations. However, realizing an active metasurface retaining lensing functionality in the THz frequency regime is still highly desired. Here a metalens, featuring electrically tunable focal length, based on propagation phase delay, is proposed and demonstrated experimentally. To have full control over the designed lens functionality, a gold thin film etched with a C-shaped aperture antenna array covered by monolayer graphene is used. By applying a bias voltage to the graphene, the phase control of the antenna array is changed, and thus the focus of the linearly polarized THz beam can be flexibly tuned from 7.13mm to 8.25mm. The proposed approach has a promising perspective for a variety of applications in communication, reconfigurable flat optics and real-time imaging in THz regime.
ISSN:1094-4087
1094-4087
DOI:10.1364/oe.381765