论文标题
拓扑光子晶体边缘状态下纳米级旋转到旋转锁定的故障
Breakdown of spin-to-helicity locking at the nanoscale in topological photonic crystal edge states
论文作者
论文摘要
我们测量拓扑边缘状态波导中的局部近场自旋，以模拟量子自旋效应。我们揭示了高度结构化的自旋密度分布，该分布与唯一的伪词值无关。从实验性近场真实空间图和数值计算中，我们确认这种局部结构对于理解光学边缘状态和光晶相互作用的性质至关重要。与远场中测得的伪蛋白相比，近场的全局自旋降低了30倍，并且在某些频率中降低了。我们通过实验揭示了高阶Bloch谐波在自旋不均匀性中的影响，从而导致局部螺旋性与全局旋转之间的耦合分解。
We measure the local near-field spin in topological edge state waveguides that emulate the quantum spin Hall effect. We reveal a highly structured spin density distribution that is not linked to a unique pseudospin value. From experimental near-field real-space maps and numerical calculations, we confirm that this local structure is essential in understanding the properties of optical edge states and light-matter interactions. The global spin is reduced by a factor of 30 in the near field and, for certain frequencies, flipped compared to the pseudospin measured in the far-field. We experimentally reveal the influence of higher-order Bloch harmonics in spin inhomogeneity, leading to a breakdown in the coupling between local helicity and global spin.
