Planar chiral metasurfaces with maximal and tunable chiroptical response driven by bound states in the continuum

Authors

• Tan Shi, Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, China
• Zi-Lan Deng, Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, ChinaFollow
• Guangzhou Geng, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
• Xianzhi Zeng, Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, China
• Yixuan Zeng, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore
• Guangwei Hu, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore
• Adam Overvig, CUNY Advanced Science Research CenterFollow
• Junjie Li, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, ChinaFollow
• Cheng-Wei Qiu, Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore
• Andrea Alù, CUNY Advanced Science Research CenterFollow
• Yuri S. Kivshar, Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra, Australia
• Xiangping Li, Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, ChinaFollow

Document Type

Article

Publication Date

2022

Abstract

Optical metasurfaces with high quality factors (Q-factors) of chiral resonances can boost substantially light-matter interaction for various applications of chiral response in ultrathin, active, and nonlinear metadevices. However, current approaches lack the flexibility to enhance and tune the chirality and Q-factor simultaneously. Here, we suggest a design of chiral metasurface supporting bound state in the continuum (BIC) and demonstrate experimentally chiroptical responses with ultra-high Q-factors and near-perfect circular dichroism (CD = 0.93) at optical frequencies. We employ the symmetry-reduced metaatoms with high birefringence supporting winding elliptical eigenstate polarizations with opposite helicity. It provides a convenient way for achieving the maximal planar chirality tuned by either breaking in-plane structure symmetry or changing illumination angle. Beyond linear CD, we also achieved strong near-field enhancement CD and near-unitary nonlinear CD in the same planar chiral metasurface design with circular eigen-polarization. Sharply resonant chirality realized in planar metasurfaces promises various practical applications including chiral lasers and chiral nonlinear filters.

Comments

This article was originally published in Nature Communications, available at https://doi.org/10.1038/s41467-022-31877-1

This work is distributed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).