Abstract-Design of dual-band polarization controllable metamaterial absorber at terahertz frequency

Ben-Xin Wang, Yuanhao He, Nianxi Xu, Xiaoyi Wang, Yanchao Wang, Jianjun Cao



https://www.sciencedirect.com/science/article/pii/S2211379720305969

Dual-band polarization controllable terahertz metamaterial absorber consisting of two horizontal metallic strips and two vertically connected metallic strips is demonstrated. Due to different strip lengths in the two orthogonal directions, two near-perfect absorption peaks are firstly obtained when the incident beam electric field is in the horizontal direction, while two new peaks are next realized when the electric field is selected along the vertical direction. The near-field distributions in two specific directions are provided to investigate the mechanism of polarization controllable dual-band absorption. Our research should have broad application prospects in the selection, control and utilization of polarization-based devices.

Abstract-Broadband achromatic metalens in terahertz regime

Qingqing Cheng, Meilin Ma, Dong Yu, Zhixiong Shen, Jingya Xie, Juncheng Wang, Nianxi Xu, Hanming Guo, Wei Hu, Shuming Wang, Tao Li, Songlin Zhuang



https://www.sciencedirect.com/science/article/pii/S2095927319304621

Achromatic focusing is essential for broadband operation, which has recently been realized from visible to infrared wavelengths using a metasurface. Similarly, multi-terahertz functional devices can be encoded in a desired metasurface phase profile. However, metalenses suffer from larger chromatic aberrations because of the intrinsic dispersion of each unit element. Here, we propose an achromatic metalens with C-shaped unit elements working from 0.3 to 0.8 THz with a bandwidth of approximately 91% over the centre frequency. The designed metalens possesses a high working efficiency of more than 68% at the peak and a relatively high numerical aperture of 0.385. We further demonstrate the robustness of our C-shaped metalens, considering lateral shape deformations and deviations in the etching depth. Our metalens design opens an avenue for future applications of terahertz meta-devices in spectroscopy, time-of-flight tomography and hyperspectral imaging systems.