Mapping the near-field spin angular momenta in the structured surface plasmon polaritons field

Abstract

Optical spin angular momenta in a confined electromagnetic field exhibit remarkable difference with their free space counterparts, in particular, the optical transverse spin that is locked with the energy propagating direction lays the foundation for many intriguing physical effects such as unidirectional transportation, quantum spin Hall effect, photonic Skyrmion, etc. In order to investigate the underlying physics behind the spin-orbit interactions as well as to develop the optical spin-based applications, it is crucial to uncover the spin texture in a confined field, yet it faces challenge due to their chiral and near-field vectorial features. Here, we propose a scanning imaging technique which can map the near-field distributions of the optical spin angular momenta with an achiral dielectric nanosphere. The spin angular momentum component normal to the interface can be uncovered experimentally by employing the proposed scanning imaging technique and the three-dimensional spin vector can be reconstructed theoretically with the experimental results. The experiment is demonstrated on the example of surface plasmon polaritons excited by various vector vortex beams under a tight-focusing configuration, where the spin-orbit interaction emerges clearly. The proposed method, which can be utilized to reconstruct the photonic Skyrmion and other photonic topological structures, is straightforward and of high precision, and hence it is expected to be valuable for the study of near-field spin optics and topological photonics.

References in corpus (5)

• Quantum spin Hall effect of light
• Chiral nanophotonic waveguide interface based on spin-orbit coupling of light
• Conservation of Angular Momentum, Transverse Shift, and Spin Hall Effect in Reflection and Refraction of Electromagnetic Wave Packet
• Geometrodynamics of Spinning Light
• Measuring the Transverse Spin Density of Light

Cited by in corpus (7)

• Photonic spin lattices: symmetry constraints for skyrmion and meron topologies
• Topological metasurface: From passive toward active and beyond
• Symmetry-protected photonic chiral spin textures by spin-orbit coupling
• Intrinsic spin-momentum dynamics of surface electromagnetic waves in complex dispersive system
• Spin/momentum properties of the paraxial optical beams
• Electrons in intense laser fields with local phase, polarization, and skyrmionic textures
• Optical polarization skyrmionic fields in free space