Quite recently, an unconventional variety of fourfold linear band degeneracy points has been discovered in certain condensed-matter systems. Contrary to standard 3-D Dirac monopoles, these quadruple points known as the charge-2 Dirac points are characterized by nonzero topological charges, which can be exploited to delve into hitherto unknown realms of topological physics. Here, we report on the experimental realization of a charge-2 Dirac point by deliberately engineering hybrid topological states, called super-modes, in a 1-D optical superlattice system with synthetic dimensions. Utilizing direct reflection and transmission measurements, we propose the existence of the synthetic charge-2 Dirac point in the visible region. We also show an experimental approach to manipulating two spawned Weyl points possessing equal charge. Topological end modes resulting from the charge-2 Dirac point can be delicately controlled within truncated superlattices, opening a pathway to rationally engineer local fields with intense enhancement.

最近，在某些凝聚态系统中发现了非常规的四重线性带简并点。与标准3D Dirac单极子相反，这些称为电荷2狄拉克点的四重点具有非零拓扑电荷的特征，可以利用这些电荷来探究迄今未知的拓扑物理学领域。在这里，我们报告通过在具有合成尺寸的一维光学超晶格系统中通过有意地工程化称为超级模式的混合拓扑状态来实现电荷2 Dirac点的实验实现。利用直接反射和透射测量，我们建议在可见光区域存在合成电荷2 Dirac点。我们还展示了一种处理具有相等电荷的两个衍生的Weyl点的实验方法。