近日，北京大学的杨起帆&刘文静&肖云峰及其研究团队取得一项新进展。经过不懈努力，他们实现集成的涡旋孤子微梳。相关研究成果已于2024年3月29日在国际知名学术期刊《自然—光子学》上发表。

该研究团队成功在光子芯片上实现了对梳状结构频率与OAM的组合控制。通过非线性环形微谐振器形成耗散光孤子，并在角光栅的作用下发射，每个梳线均携带不同的OAM。这种涡旋孤子微梳的光束展现出动态旋转的双螺旋强度分布特性。OAM与频率之间的一对一对应关系，其消光比高达18.5dB以上，为光学涡旋的精确光谱分析提供了可能。

此项研究为在空间和频率域中实现相干光源复用提供了集成的解决方案，有望开启一种产生高维结构光的新途径。

据悉，光的频率与轨道角动量（OAM）的协同控制为时空光波形的生成以及光学测量提供了全新机遇。不过，由于在高维OAM状态的生成、操纵与检测方面存在诸多困难，其物理实现过程往往显得笨拙且复杂。

附：英文原文

Title: Integrated vortex soliton microcombs

Author: Liu, Yanwu, Lao, Chenghao, Wang, Min, Cheng, Yinke, Wang, Yuanlei, Fu, Shiyao, Gao, Chunqing, Wang, Jianwei, Li, Bei-Bei, Gong, Qihuang, Xiao, Yun-Feng, Liu, Wenjing, Yang, Qi-Fan

Issue&Volume: 2024-03-29

Abstract: Synergistic control of the frequency and orbital angular momentum (OAM) of light offers new opportunities for the generation of spatio-temporal optical waveforms and optical metrology. However, their physical realizations are typically bulky and complex owing to challenges in creating, manipulating and detecting mutually coherent, high-dimensional OAM states. Here we achieve combined control over the frequency and the OAM of a comb structure on a photonic chip. Dissipative optical solitons are formed in a nonlinear ring microresonator and emitted owing to engraved angular gratings, with each comb line carrying a distinct OAM. The beam of such a vortex soliton microcomb manifests dynamically revolving, double-helical intensity profiles. The one-to-one correspondence between the OAM and frequencies features a high extinction ratio of over 18.5dB, enabling precision spectroscopy of optical vortices. Our work provides an integrated solution for realizing coherent light sources that are multiplexed in the spatial and frequency domains, with the potential to establish a new approach to the generation of high-dimensional structured light.

DOI: 10.1038/s41566-024-01418-x

Source: https://www.nature.com/articles/s41566-024-01418-x