Oliwa Przemysław, Kapuściński Piotr, Popławska Maria, Muszyński Marcin, Król Mateusz, Morawiak Przemysław, Mazur Rafał, Piecek Wiktor, Kula Przemysław, Bardyszewski Witold, Piętka Barbara, Sigurðsson Helgi, Szczytko Jacek
Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, Warsaw, PL-02-093, Poland.
Institute of Applied Physics, Military University of Technology, ul. gen. Kaliskiego 2, Warsaw, PL-00-908, Poland.
Adv Sci (Weinh). 2025 Jun;12(23):e2500060. doi: 10.1002/advs.202500060. Epub 2025 May 14.
Momentum space polarization singularities of light appear as vectorial twists in the scattered and radiated far field patterns of exotic photonic structures. They relate to important concepts such as bound states in the continuum, spatiotemporal light steering, polarization Möbius strips, Berry curvature, and associated topological photonic phenomena. Polarization singularities, such as completely circularly polarized C-points, are readily designed in real space through interference of differently polarized beams. In momentum space, they require instead sophisticated patterning of photonic crystal slabs of reduced symmetries in order to appear in the corresponding band structure with scarce in situ tunability. Here, it is shown that momentum space singularities can be generated and, importantly, electrically tuned in the band structure of a highly birefringent planar liquid crystal microcavity that retains many symmetries. The results agree with theoretical predictions and offer exciting possibilities for integration of momentum space polarization singularities in spinoptronic technologies.
光的动量空间偏振奇点表现为奇特光子结构散射和辐射远场图案中的矢量扭曲。它们与诸如连续统中的束缚态、时空光操控、偏振莫比乌斯带、贝里曲率以及相关拓扑光子现象等重要概念相关。偏振奇点，例如完全圆偏振的C点，可通过不同偏振光束的干涉在实空间中轻松设计。而在动量空间中，为了使其出现在具有稀缺原位可调性的相应能带结构中，需要对对称性降低的光子晶体平板进行复杂的图案化处理。在此，研究表明，在保留许多对称性的高双折射平面液晶微腔的能带结构中，可以产生动量空间奇点，并且重要的是可以进行电调谐。结果与理论预测相符，并为在自旋光电子技术中集成动量空间偏振奇点提供了令人兴奋的可能性。
