带宽可调谐的太赫兹超构材料半波片器件

Bandwidth-tunable terahertz metamaterial half-wave plate component

基于二氧化钒(vanadium dioxide,VO_(2))的相变原理,提出了一种“树叶型”复合超构材料,能够实现带宽可调谐的半波片功能。VO_(2)薄膜为绝缘态时,复合超构材料可以看作是空芯“树叶型”金属结构,能够实现双频带的半波片功能。在1.01~1.17 THz和1.47~1.95 THz频带范围内能够将y偏振光转换成x偏振光,偏振转换率大于0.9且平均相对带宽为26%。VO_(2)薄膜为金属态时,实芯“树叶型”金属结构的超构材料在1.13~2.80 THz范围内能够实现反射型的宽频带半波片功能,相对带宽为85%。利用瞬时表面电流分布和电场理论详细地分析了带宽可调谐半波片器件的工作原理。本文所提出的“树叶型”复合超构材料半波片器件在太赫兹成像、传感和偏振探测等领域具有潜在的应用前景。

We propose a“leaf-type”hybrid metamaterial to realize bandwidth-tunable half-wave plate based on vanadium dioxide(VO_(2))phase transition.The hybrid metamaterial is regarded as a hollow“leaf-type”metallic structure and act as a dual-band half-wave plate when VO_(2)film is in the insulating phase.Within 1.01−1.17 THz and 1.47−1.95 THz,it can accomplish y-to x-polarization conversion with a polarization conversion rate over 0.9 and an average relative bandwidth of 26%.The metamaterial becomes a solid core“leaftype”metallic structure when VO_(2)is in the metallic phase.Within 1.13−2.80 THz,it can act as a broadband half-wave plate with a relative bandwidth of 85%.The working principle of the bandwidth-tunable half-wave plate is explained by the instantaneous surface current distribution and electric field theory in detail.The proposed“leaf-type”hybrid metamaterial half-wave plate has potential application prospects in THz imaging,sensing and polarization detection.