Helicity and Angular Momentum. A Symmetry based framework for the study of Light-Matter Interactions
Ivan Fernandez-Corbaton, Xavier Zambrana-Puyalto, Gabriel Molina-Terriza
备注：
34 pages, 4 figures, http://link.aps.org/doi/10.1103/PhysRevA.86.042103. v4: corrected typo (loose bracket) in formulas 15 and B13, which are actually the same formulas. Replaced Fig 3a and 3b to correct wrong labels of the horizontal axis
We propose a new theoretical and practical framework for the study of light-matter interactions and the angular momentum of light. Our proposal is based on helicity, total angular momentum, and the use of symmetries. We compare the new framework to the current treatment, which is based on separately considering spin angular momentum and orbital angular momentum and using the transfer between the two in physical explanations. In our proposal, the fundamental problem of spin and orbital angular momentum separability is avoided, predictions are made based on the symmetries of the systems, and the practical application of the concepts is straightforward. Finally, the framework is used to show that the concept of spin to orbit transfer applied to focusing and scattering is masking two completely different physical phenomena related to the breaking of different fundamental symmetries: transverse translational symmetry in focusing and electromagnetic duality symmetry in scattering.
Tailoring multipolar Mie scattering with helicity and angular momentum
线性散射过程通常被描述为入射光束参数的函数。其中包括波长、强度分布、偏振或相位。在这里，我们讨论和实验证明如何角动量和螺旋度的光的球形粒子的光散射的影响。我们测量了沉积在玻璃衬底上的$4μm$ TiO $_2$单粒子的背散射。粒子在不同的波长探测不同的光束与总角动量范围从$-8$到$+8$单位。观察到粒子的光谱行为高度依赖于入射光束的角动量和螺旋度。虽然散射场的一些特性可以用简单的谐振腔模型来描述，但高角动量光束的散射需要对球体中诱导的多极模式有更深入的了解。我们观察到，剪裁这些诱导的多极模式可以导致偏移和光谱窄化的散射光谱的峰值。此外，螺旋度和角动量的激发的特定组合导致系统的螺旋度守恒的差异，这对散射图案有明显的影响。
Optical forces, helicity, angular momentum and how they are all intertwined
Centro de Física de Materiales (CFM), CSIC-UPV/EHU（材料物理中心，西班牙科学研究中心-巴斯克国立大学）；Donostia International Physics Center（圣塞巴斯蒂安国际物理中心）；Basic Sciences Department, Mondragon Unibertsitatea（蒙德拉贡大学基础科学系）；IKERBASQUE, Basque Foundation for Science（伊克尔巴斯基，巴斯克科学基金会）
Electromagnetic duality symmetry and helicity conservation for the macroscopic Maxwell's equations (previously "Experimental demonstration of electromagnetic duality symmetry breaking")
Circular Raman responses from angular-momentum inequivalence in CoSi
Institute of Science Tokyo（东京科学大学）；Hokkaido University（北海道大学）；The University of Tokyo（东京大学）；RIKEN（理化学研究所）；Okayama University（冈山大学）；Osaka Metropolitan University（大阪公立大学）；Institute for Molecular Science（分子科学研究所）
本文通过圆偏振拉曼光谱和第一性原理计算，证明 CoSi 中拉曼光学活性和手性声子频率分裂源于不同对称性通道，提出角动量不等价是圆偏振拉曼响应的统一原理。
