Open AccessAn ultrathin terahertz lens with axial long focal depth based on metasurfaces
Author(s) -
Xiaoyan Jiang,
Jiasheng Ye,
Jingwen He,
Xinke Wang,
Dan Hu,
Shengfei Feng,
Qiang Kan,
Yan Zhang
Publication year - 2013
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.21.030030
Subject(s) - terahertz radiation , optics , lens (geology) , materials science , photolithography , optoelectronics , metamaterial , plasmon , phase modulation , lithography , silicon , physics , phase noise
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.