An ultrathin terahertz lens with axial long focal depth based on metasurfaces

The plasmonic resonance effect on metasurfaces generates an abrupt phase change. We employ this phase modulation mechanism to design the longitudinal field distribution of an ultrathin terahertz (THz) lens for achieving the axial long-focal-depth (LFD) property. Phase distributions of the designed l...

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Bibliographic Details
Published in:Optics express 2013-12, Vol.21 (24), p.30030-30038
Main Authors: Jiang, Xiao-Yan, Ye, Jia-Sheng, He, Jing-Wen, Wang, Xin-Ke, Hu, Dan, Feng, Sheng-Fei, Kan, Qiang, Zhang, Yan
Format: Article
Language:English
Subjects:
Equipment Design
Equipment Failure Analysis
Lenses
Membranes, Artificial
Nanotechnology - instrumentation
Terahertz Radiation
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Summary:The plasmonic resonance effect on metasurfaces generates an abrupt phase change. We employ this phase modulation mechanism to design the longitudinal field distribution of an ultrathin terahertz (THz) lens for achieving the axial long-focal-depth (LFD) property. Phase distributions of the designed lens are obtained by the Yang-Gu iterative amplitude-phase retrieval algorithm. By depositing a 100 nm gold film on a 500 μm silicon substrate and etching arrayed V-shaped air holes through the gold film, the designed ultrathin THz lens is fabricated by the micro photolithography technology. Experimental measurements have demonstrated its LFD property, which basically agree with the theoretical simulations. In addition, the designed THz lens possesses a good LFD property with a bandwidth of 200 GHz. It is expected that the designed ultrathin LFD THz lens should have wide potential applications in broadband THz imaging and THz communication systems.
ISSN:1094-4087
1094-4087
DOI:10.1364/OE.21.030030