Abstract-Multi-foci metalens for terahertz polarization detection

Ruoxing Wang, Jin Han, Jianlong Liu, Hao Tian, Weimin Sun, Li Li, and Xianzhong Chen

Schematic of the reflective THz multi-foci metalens for polarization detection. The ellipticity angle 𝜒$\chi$ and the direction of the major axis 𝛽$\beta$ of the incident and reflected polarization states are indicated in polarization ellipses.

https://www.osapublishing.org/ol/abstract.cfm?URI=ol-45-13-3506

We propose a reflective terahertz (THz) metalens with four focal points for polarization detection of THz beams. The metalens is composed of 𝑍$Z$-shaped resonators with spatially variant orientations, a reflective gold layer, and a dielectric spacer between them. The polarization states of the focal points include left circular polarization, right circular polarization, an incident polarization state, and a polarization state whose major axis is rotated 𝜋/4$\pi /4$ in comparison with that of the incident polarization. The handedness, ellipticity, and major axis of the polarization state can be determined based on the light intensities of the focal points. The uniqueness of the designed device renders this technique very attractive for applications in compact THz polarization detection and information processing.

Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Abstract-A Multi‐Foci Metalens with Polarization‐Rotated Focal Points

Xiaofei Zang, Hongzhen Ding,   Yuttana Intaravanne,   Lin Chen,   Yan Peng,   Jingya Xie,   Qinghong Ke,   Alexey V. Balakin,   Alexander P. Shkurinov,   Xianzhong Chen, Yiming Zhu,   Songlin Zhuang,

https://onlinelibrary.wiley.com/doi/abs/10.1002/lpor.201900182

Benefiting from the unprecedented capability of metasurfaces in the manipulation of light propagation, metalenses can provide novel functions that are very challenging or impossible to achieve with conventional lenses. Here, an approach to realizing multi‐foci metalenses is proposed and experimentally demonstrated with polarization‐rotated focal points based on geometric metasurfaces. Multi‐foci metalenses with various polarization rotation directions are developed using silicon pillars with spatially variant orientations. The focusing characteristic and longitudinal polarization‐dependent imaging capability are demonstrated upon the illumination of a linearly polarized light beam. The uniqueness of this multi‐foci metalens with polarization‐rotated focal points may open a new avenue for imaging, sensing, and information processing.