Simultaneous sorting of arbitrary vector structured beams with spin-multiplexed diffractive metasurfaces

• Published in: Advanced Photonics Nexus Vol. 3; no. 3; p. 036010
• Main Authors: Li, Xiaoxin, Feng, Rui, Sun, Fangkui, Zhang, Yanxia, Jia, Qi, Tang, Donghua, Shi, Bojian, Li, Hang, Gao, Yanyu, Gao, Wenya, Cao, Yongyin, Ding, Weiqiang
• Format: Journal Article
• Language: English
• Published: Society of Photo-Optical Instrumentation Engineers 01.05.2024; SPIE
• Subjects: Neural networks; vector structured beams; polarization-multiplexed metasurfaces; mode sorting; diffractive optical neural networks
• ISSN: 2791-1519; 2791-1519
• DOI: 10.1117/1.APN.3.3.036010

Vector structured beams (VSBs) offer infinite eigenstates and open up new possibilities for high-capacity optical and quantum communications by the multiplexing of the states. Therefore, the sorting and measuring of VSBs are extremely important. However, the efficient manipulations of a large number of VSBs have simultaneously remained challenging up to now, especially in integrated optical systems. Here, we propose a compact spin-multiplexed diffractive metasurface capable of continuously sorting and detecting arbitrary VSBs through spatial intensity separation. By introducing a diffractive optical neural network with cascaded metasurface systems, we demonstrate arbitrary VSBs sorters that can simultaneously identify Laguerre–Gaussian modes (l=−4 to 4, p=1 to 4), Hermitian–Gaussian modes (m=1 to 4, n=1 to 3), and Bessel–Gaussian modes (l=1 to 12). Such a sorter for arbitrary VSBs could revolutionize applications in integrated and high-dimensional optical communication systems.