Li Jiu-Sheng, Li Xiang-Jun
Opt Express. 2022 Apr 11;30(8):12823-12834. doi: 10.1364/OE.454240.
A terahertz switchable metasurface with the function of absorption and polarization conversion is proposed. It consists of metal pattern layer - dielectric layer - VO layer - dielectric layer - metal pattern layer, and the photosensitive silicon is embedded in the metal pattern. When VO is in insulated state, the metasurface behaves as a linear polarization converter. The polarization conversion rate (PCR) is more than 90% at two frequency bands of 1.64 THz ∼ 1.91 THz and 2.35 THz ∼ 2.75 THz. The polarization converter has good asymmetric transmission ability. Moreover, the polarization conversion performance can be dynamically controlled by changing the conductivity of the photosensitive silicon. When VO is in metallic state, the metasurface becomes a terahertz bidirectional absorber, which exhibits different absorption properties under TE and TM waves with the maximum absorptance reaching to 100%. In addition, the absorption of TE and TM terahertz waves can be controlled at the specific frequency by changing the conductivity of photosensitive silicon. We also explore the application of dynamic control of polarization waves in the near-field image display.
提出了一种具有吸收和偏振转换功能的太赫兹可切换超表面。它由金属图案层-介质层-VO层-介质层-金属图案层组成，且光敏硅嵌入在金属图案中。当VO处于绝缘状态时，超表面表现为线性偏振转换器。在1.64太赫兹至1.91太赫兹和2.35太赫兹至2.75太赫兹两个频段，偏振转换率（PCR）超过90%。该偏振转换器具有良好的非对称传输能力。此外，通过改变光敏硅的电导率，可以动态控制偏振转换性能。当VO处于金属状态时，超表面成为太赫兹双向吸收器，在TE波和TM波下表现出不同的吸收特性，最大吸收率达到100%。另外，通过改变光敏硅的电导率，可以在特定频率下控制TE和TM太赫兹波的吸收。我们还探索了偏振波动态控制在近场图像显示中的应用。
