扭曲的莫尔光子晶体通过连续统中的束缚态实现光学涡旋的产生。

Twisted moiré photonic crystal enabled optical vortex generation through bound states in the continuum.

作者信息

Zhang Tiancheng, Dong Kaichen, Li Jiachen, Meng Fanhao, Li Jingang, Munagavalasa Sai, Grigoropoulos Costas P, Wu Junqiao, Yao Jie

机构信息

Applied Science and Technology Graduate Group, University of California, Berkeley, CA, 94720, USA.

Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.

出版信息

Nat Commun. 2023 Sep 27;14(1):6014. doi: 10.1038/s41467-023-41068-1.

DOI:10.1038/s41467-023-41068-1

PMID:37758708

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10533549/

Abstract

The twisted stacking of two layered crystals has led to the emerging moiré physics as well as intriguing chiral phenomena such as chiral phonon and photon generation. In this work, we identified and theoretically formulated a non-trivial twist-enabled coupling mechanism in twisted bilayer photonic crystal (TBPC), which connects the bound state in the continuum (BIC) mode to the free space through the twist-enabled channel. Moreover, the radiation from TBPC hosts an optical vortex in the far field with both odd and even topological orders. We quantitatively analyzed the twist-enabled coupling between the BIC mode and other non-local modes in the photonic crystals, giving rise to radiation carrying orbital angular momentum. The optical vortex generation is robust against geometric disturbance, making TBPC a promising platform for well-defined vortex generation. As a result, TBPCs not only provide a new approach to manipulating the angular momentum of photons, but may also enable novel applications in integrated optical information processing and optical tweezers. Our work broadens the field of moiré photonics and paves the way toward the novel application of moiré physics.

摘要

两个层状晶体的扭曲堆叠导致了新兴的莫尔物理学以及诸如手性声子和光子产生等有趣的手性现象。在这项工作中，我们在扭曲双层光子晶体（TBPC）中识别并从理论上阐述了一种非平凡的扭曲驱动耦合机制，该机制通过扭曲启用通道将连续统中的束缚态（BIC）模式与自由空间相连。此外，TBPC的辐射在远场中具有奇数和偶数拓扑序的光学涡旋。我们定量分析了光子晶体中BIC模式与其他非局域模式之间的扭曲驱动耦合，产生了携带轨道角动量的辐射。光学涡旋的产生对几何扰动具有鲁棒性，使TBPC成为产生明确涡旋的有前途的平台。因此，TBPC不仅提供了一种操纵光子角动量的新方法，还可能在集成光学信息处理和光镊中实现新颖应用。我们的工作拓宽了莫尔光子学领域，并为莫尔物理学的新颖应用铺平了道路。