光栅-液晶复合结构太赫兹移相器

随着太赫兹技术及其应用的快速发展，各类太赫兹控制器件需求也随之增加，作为太赫兹系统重要器件之一，太赫兹波移相器成为当前研究热点。已有移相器存在着尺寸较大、结构复杂、相移量较小等问题，为克服上述缺陷，提出一种光栅-液晶复合结构太赫兹移相器，该器件结构为石英、石墨烯、液晶盒、光栅结构、石墨烯和石英组成。通过改变石墨烯电极上电压，使液晶折射率发生改变，相移器的相位因折射率改变而发生变化，通过控制外加电压可以实现对太赫兹波相移量有效调控。计算结果表明，该移相器在0.39~0.46 THz频率范围内实现了400°相移量，回波损耗小于-11 dB，在频率0.43 THz处，最大相移量达到422°。太赫兹波入射角在0°~30°范围内变化，移相器的相移量保持不变，而且该器件对入射太赫兹波偏振态不敏感。所设计的太赫兹移相器具有相移量大、结构尺寸小等优点，在未来的太赫兹通信、安检、医疗、传感、成像等领域中具有广阔的应用前景。

Terahertz Phase Shifter Based on Grating-Liquid Crystal Hybrid Structure

With the rapid development of terahertz technology and its application, the demand for various kinds of terahertz manipulation devices increases as one of the important components of the terahertz system, the terahertz wave phase shifter has become a research hotspot. The reported terahertz wave phase shifters have large size, complex structure and small phase shift problems. In order to overcome the above defects, we proposed a novel terahertz phase shifter based on a grating liquid crystal composite structure. It is composed of quartz layer, graphene layer, liquid crystal cell, grating structure, graphene layer and quartz layer. By changing the voltage on graphene, the refractive index of the liquid crystal can be varied, and the phase of the proposed terahertz phase shifter will change due to the change of refractive index. Then, the phase shift of the proposed terahertz wave phase shifter can be effectively adjusted by controlling the externally applied voltage. The simulation results show that the phase shifter achieves 400° phase shift in the frequency range from 0.39 to 0.46 THz, and the return loss is less than -11 dB. The maximum phase shift is 422° at a frequency of 0.43 THz. When the incident angle of the terahertz wave varies from 0 ° to 30 °, the phase shift of the proposed phase shifter remains unchanged. In addition, the device is insensitive to the polarization state of the incident terahertz wave. The designed terahertz phase shifter has the advantages of a large phase shift and small structure size. It has widespread applications prospects in the future terahertz communication, security inspection, medical, sensing, imaging, etc.