Rao Lixi, Wang Jiajun, Wang Xinhao, Wu Shunben, Zhao Xingqi, Liu Wenzhe, Xie Rensheng, Shen Yijie, Shi Lei, Zi Jian
Fudan University, State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonic Structures (Ministry of Education) and Department of Physics, Shanghai 200433, China.
Fudan University, Institute for Nanoelectronic Devices and Quantum Computing, Shanghai 200438, China.
Phys Rev Lett. 2025 Jul 11;135(2):026203. doi: 10.1103/3g3j-mnh9.
Topological spin textures, such as merons and skyrmions, have shown significance in both fundamental science and practical applications across diverse physical systems. The optical skyrmionic textures in real space have been extensively explored, but those in momentum space are still rarely studied. Here, we report the experimental generation of momentum-space meron spin textures via bound states in the continuum (BICs) in photonic crystal slabs. We show that under circularly polarized illumination, the momentum-space vortex topology of BICs can transform light with meron spin textures in momentum space. These merons exhibit polarity-switchable configurations controlled by incident light polarization. We theoretically and experimentally verify the generation of momentum-space merons and demonstrate their operational flexibility across a broad spectral range. Our results establish a connection between different momentum-space topologies and provide a robust and compact platform for generating topological spin textures.
诸如磁单极子和斯格明子等拓扑自旋纹理在各种物理系统的基础科学和实际应用中都显示出重要意义。实空间中的光学斯格明子纹理已得到广泛研究，但动量空间中的此类纹理仍鲜有研究。在此，我们报告了通过光子晶体平板中的连续统束缚态（BICs）实验生成动量空间磁单极子自旋纹理。我们表明，在圆偏振照明下，BICs的动量空间涡旋拓扑结构可在动量空间中变换具有磁单极子自旋纹理的光。这些磁单极子呈现出由入射光偏振控制的极性可切换构型。我们通过理论和实验验证了动量空间磁单极子的生成，并展示了它们在宽光谱范围内的操作灵活性。我们的结果建立了不同动量空间拓扑之间的联系，并为生成拓扑自旋纹理提供了一个强大且紧凑的平台。
