Programmable pure phase spatial terahertz modultor
Yan Zhang, Jinying Guo, Teng Wang, Huan Zhao and Xinke Wang
Department of Physics, Capital Normal University, Beijing Key Laboratory of Metamaterials and
Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, and Beijing Advanced
Innovation Center for Imaging Technology, Bei
: J Electr Eng Electron Technol
Terahertz (THz) radiation has many potential applications. However, comparing with the rapid development of THz sources and detectors, the functional devices for THz modulation, especially the spatial modulation devices, are still insufficiency. Here, we present a novel approach for generating arbitrary wavefronts of a THz beam by dynamically creating metasurface structures through illuminating a thin silicon wafer with femtosecond laser, which is spatially modulated to result in an array of reconfigurable subwavelength resonators. The wavefront of the THz beam is then determined by forming spatial profiles of the Pancharatnam-Berry scattering phase by dynamically controlling the resonator orientation. Proof-of-concept experiments demonstrate that streaming holographic images and lenses of variable focal length can be realized in real time. The reconfigurable scheme demonstrated here is convenient and fast, and may lead to advances in a host of THz applications.
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