Gangwar Kapil K, Bansal Sarvesh, Senthilkumaran P
J Opt Soc Am A Opt Image Sci Vis. 2024 May 1;41(5):932-942. doi: 10.1364/JOSAA.521031.
In this paper, a novel methodology for generating polarization singularity lattices using ramp phase structures in a polarization interferometer is presented. By applying differential tilts to distinct regions within the wavefront using a spatial light modulator, a phase-discontinuity line separating the two regions is formed. During propagation along this line, phase vortices are formed at discrete points about which the phase difference on either side of the ramp is . This wavefront with phase vortices is superimposed with a plane wave in orthogonal polarization in a polarization interferometer, giving rise to polarization singularities. A common-path polarization interferometer is constructed using a spatial light modulator to reduce errors and complexity. Polarization fringes instead of intensity fringes obtained in this interferometer host polarization singularities. Lattices made up of a linear chain of polarization singularities-unusually of the same index polarity-are found here. Experimental results corroborate the theoretical predictions. This study shows that singularities can be produced with non-spiral phase plates by using linear phase ramps. The method discussed in this paper may find potential applications in optical trapping and particle steering.
本文提出了一种在偏振干涉仪中利用斜坡相位结构生成偏振奇点晶格的新方法。通过使用空间光调制器对波前内的不同区域施加不同的倾斜，形成了分隔这两个区域的相位不连续线。沿着这条线传播时，在斜坡两侧相位差为的离散点处会形成相位涡旋。这种带有相位涡旋的波前在偏振干涉仪中与正交偏振的平面波叠加，从而产生偏振奇点。使用空间光调制器构建了共光路偏振干涉仪，以减少误差和复杂性。在此干涉仪中获得的是偏振条纹而非强度条纹，这些条纹承载着偏振奇点。在此发现了由线性链状偏振奇点组成的晶格，通常具有相同的指数极性。实验结果证实了理论预测。这项研究表明，通过使用线性相位斜坡，可以用非螺旋相位板产生奇点。本文所讨论的方法可能在光学捕获和粒子操纵方面找到潜在应用。
