旋转Umklapp过程辅助下磁振子诱导的光学涡旋与高斯光束散射共存现象
Coexistence of Magnon-Induced Optical Vortex and Gaussian Beam Scattering Assisted by Rotational Umklapp Process
AI总结：
该研究通过实验证实特定铁磁晶体取向下，旋转Umklapp过程可提供缺失角动量，使高斯光束散射与光学涡旋散射共存，并预测光聚焦程度增加会反转二者相对效率。
AI中文摘要：
利用晶体晶格对称性调控结构化光与磁振子之间的角动量转移，是光磁子学研究的新前沿。在布里渊光散射中，当聚焦光平行于外磁场传播并与铁磁均匀磁振子相互作用时，仅预期允许光学涡旋散射。由于磁光耦合与光学自旋-轨道相互作用的共同作用，磁振子自旋角动量向光子轨道角动量的转移，促成了这一独特散射现象。本文实验证实，对于特定铁磁晶体取向，高斯光束散射与光学涡旋散射共存，这与基于磁振子与光子角动量守恒的传统预期相悖。研究表明，晶体晶格通过旋转Umklapp过程，为高斯光束散射提供了所需的缺失角动量。此外，本文预测，随着光聚焦程度增加，高斯光束与光学涡旋散射过程的相对效率会发生反转。
英文摘要：
The exploitation of crystal-lattice symmetries to engineer angular momentum transfer between structured light and magnons marks a novel frontier for optomagnonic research. In Brillouin light scattering, when focused light propagates parallel to an external magnetic field and interacts with ferromagnetic uniform magnons, only optical-vortex scattering is expected to be permitted. Due to the combined effects of magneto-optical coupling and optical spin-orbit interaction, the transfer of magnon spin angular momentum to photon orbital angular momentum allows for this distinctive scattering phenomenon. Here, we experimentally demonstrate that, for a specific ferromagnetic crystal orientation, Gaussian-beam scattering coexists with the optical-vortex scattering, contrary to conventional expectations based on angular momentum conservation between magnons and photons. We show that the crystal lattice, via the rotational Umklapp process, provides the missing angular momentum required for the Gaussian-beam scattering. Furthermore, we predict that as the degree of light focusing increases, the relative efficiencies of the Gaussian-beam and optical-vortex scattering processes reverse.
