• Photonics Research
  • Vol. 9, Issue 10, 10001939 (2021)
Jie Li1, Chenglong Zheng1, Jitao Li1, Guocui Wang2、3, Jingyu Liu2, Zhen Yue1, Xuanruo Hao1, Yue Yang1, Fuyu Li4, Tingting Tang4, Yating Zhang1、5、*, Yan Zhang2、6、*, and Jianquan Yao1、7、*
Author Affiliations
  • 1Key Laboratory of Opto-Electronics Information Technology (Tianjin University), Ministry of Education, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
  • 2Beijing Key Laboratory for Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, and Beijing Advanced Innovation Center for Imaging Technology, Department of Physics, Capital Normal University, Beijing 100048, China
  • 3Beijing Engineering Research Center for Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
  • 4Information Materials and Device Applications Key Laboratory of Sichuan Provincial Universities, Chengdu University of Information Technology, Chengdu 610225, China
  • 5e-mail: yating@tju.edu.cn
  • 6e-mail: yzhang@mail.cnu.edu.cn
  • 7e-mail: jqyao@tju.edu.cn
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    Abstract

    Polarization manipulation of electromagnetic wave or polarization multiplexed beam shaping based on metasurfaces has been reported in various frequency bands. However, it is difficult to shape the beam with multi-channel polarization conversion in a single metasurface. Here, we propose a new method for terahertz wavefront shaping with multi-channel polarization conversion via all-silicon metasurface, which is based on the linear shape birefringence effect in spatially interleaved anisotropic meta-atoms. By superimposing the eigen- and non-eigen-polarization responses of the two kinds of meta-atoms, we demonstrate the possibility for high-efficiency evolution of several typical polarization states with two independent channels for linearly polarized waves. The measured polarization conversion efficiency is higher than 70% in the range of 0.9–1.3 THz, with a peak value of 89.2% at 1.1 THz. In addition, when more other polarization states are incident, combined with the integration of sub-arrays, we can get more channels for both polarization conversion and beam shaping. Simulated and experimental results verify the feasibility of this method. The proposed method provides a new idea for the design of terahertz multi-functional metadevices.

    1. INTRODUCTION

    Polarization is an important variable of electromagnetic waves, typical types of which include linear, circular, and elliptical ones. From the perspective of electromagnetic field, it refers to the trajectory of the electric field vibration, and from the perspective of the photons, it (circular polarization) can also be related to the spin angular momentum [1,2]. Therefore, polarization of light has been widely studied and applied in imaging, quantum optics, and other fields, and polarization manipulation has become an important research content of modern optics and photonics [35]. Traditional optical devices based on bulk crystals are used for polarization generation or conversion, such as polarizers and wave plates. The wave plate is based on the linear birefringence effect of the optical crystal, which produces a phase shift between the ordinary and the extraordinary components with an appropriate thickness, and then superimposes them into a new polarization. Such devices are large in size and require high processing accuracy, while only specific materials can be used in each electromagnetic band [6]. More importantly, these devices can hardly realize the simultaneous control of other optical parameters while performing polarization conversion, such as amplitude and phase. This is not conducive to the multi-functional and integrated development of modern optical devices.

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    Jie Li, Chenglong Zheng, Jitao Li, Guocui Wang, Jingyu Liu, Zhen Yue, Xuanruo Hao, Yue Yang, Fuyu Li, Tingting Tang, Yating Zhang, Yan Zhang, Jianquan Yao. Terahertz wavefront shaping with multi-channel polarization conversion based on all-dielectric metasurface[J]. Photonics Research, 2021, 9(10): 10001939
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    Category: Nanophotonics and Photonic Crystals
    Received: May. 10, 2021
    Accepted: Jul. 24, 2021
    Published Online: Sep. 9, 2021
    The Author Email: Yating Zhang (yating@tju.edu.cn), Yan Zhang (yzhang@mail.cnu.edu.cn), Jianquan Yao (jqyao@tju.edu.cn)