Creating pairs of exceptional points for arbitrary polarization control: asymmetric vectorial wavefront modulation

Zijin Yang; Po-Sheng Huang; Yu-Tsung Lin; Haoye Qin; Jesús Zúñiga-Pérez; Yuzhi Shi; Zhanshan Wang; Xinbin Cheng; Man-Chung Tang; Sanyang Han; Boubacar Kanté; Bo Li; Pin Chieh Wu; Patrice Genevet; Qinghua Song

doi:10.1038/s41467-023-44428-z

Creating pairs of exceptional points for arbitrary polarization control: asymmetric vectorial wavefront modulation

Nat Commun. 2024 Jan 4;15(1):232. doi: 10.1038/s41467-023-44428-z.

Authors

Zijin Yang^#^{1

2}, Po-Sheng Huang^#³, Yu-Tsung Lin³, Haoye Qin¹, Jesús Zúñiga-Pérez^{4

5}, Yuzhi Shi⁶, Zhanshan Wang⁶, Xinbin Cheng⁶, Man-Chung Tang¹, Sanyang Han¹, Boubacar Kanté⁷, Bo Li^{1

8}, Pin Chieh Wu^{9

10

11}, Patrice Genevet^{12

13}, Qinghua Song^{14

15}

Affiliations

¹ Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
² School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
³ Department of Photonics, National Cheng Kung University, Tainan, 70101, Taiwan.
⁴ Université Cote d'Azur, CNRS, CRHEA, Rue Bernard Gregory, Sophia Antipolis, 06560, Valbonne, France.
⁵ Majulab, International Research Laboratory IRL 3654, CNRS, Université Côte d'Azur, Sorbonne Université, National University of Singapore, Nanyang Technological University, Singapore, Singapore.
⁶ Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China.
⁷ Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA.
⁸ Suzhou Laboratory, Suzhou, 215123, China.
⁹ Department of Photonics, National Cheng Kung University, Tainan, 70101, Taiwan. pcwu@gs.ncku.edu.tw.
¹⁰ Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, 70101, Taiwan. pcwu@gs.ncku.edu.tw.
¹¹ Meta-nanoPhotonics Center, National Cheng Kung University, Tainan, 70101, Taiwan. pcwu@gs.ncku.edu.tw.
¹² Université Cote d'Azur, CNRS, CRHEA, Rue Bernard Gregory, Sophia Antipolis, 06560, Valbonne, France. patrice.genevet@mines.edu.
¹³ Physics Department, Colorado School of Mines, 1523 Illinois St., Golden, CO, 80401, USA. patrice.genevet@mines.edu.
¹⁴ Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China. song.qinghua@sz.tsinghua.edu.cn.
¹⁵ Suzhou Laboratory, Suzhou, 215123, China. song.qinghua@sz.tsinghua.edu.cn.

^# Contributed equally.

Abstract

Exceptional points (EPs) can achieve intriguing asymmetric control in non-Hermitian systems due to the degeneracy of eigenstates. Here, we present a general method that extends this specific asymmetric response of EP photonic systems to address any arbitrary fully-polarized light. By rotating the meta-structures at EP, Pancharatnam-Berry (PB) phase can be exclusively encoded on one of the circular polarization-conversion channels. To address any arbitrary wavefront, we superpose the optical signals originating from two orthogonally polarized -yet degenerate- EP eigenmodes. The construction of such orthogonal EP eigenstates pairs is achieved by applying mirror-symmetry to the nanostructure geometry flipping thereby the EP eigenmode handedness from left to right circular polarization. Non-Hermitian reflective PB metasurfaces designed using such EP superposition enable arbitrary, yet unidirectional, vectorial wavefront shaping devices. Our results open new avenues for topological wave control and illustrate the capabilities of topological photonics to distinctively operate on arbitrary polarization-state with enhanced performances.

Grants and funding

12204264/National Natural Science Foundation of China (National Science Foundation of China)