Light angular momentum is used to characterize the dynamical rotation of electromagnetic wave, as spin angular momentum describes its polarization rotation while orbital angular momentum describes its phase rotation. Though various methods have been proposed to detect light spin or orbital angular momentum independently, it is still a challenge to determine both of them simultaneously. Here, based on orthogonal nanoslit pairs located in semi-ring array, we design an on-chip simultaneous light spin and orbital angular momentum detector, which can generate focus at different positions sensitive to light angular momenta, thus both spin and orbital angular momenta of the indecent light can be determined. It is verified that spin angular momenta of ±1 and orbital angular momenta in wide detection range can be simultaneously determined in high accuracy; moreover, mixed light with multiple spin and orbital angular momenta can also be distinguished. Therefore, the proposed detector provides a way to determine light angular momenta in nanoscale, and can be future applied in the fields of on-chip photonics and plasmonics.

轻的角动量用于表征电磁波的动态旋转，因为自旋角动量描述了其极化旋转，而轨道角动量描述了其相位旋转。尽管已经提出了各种方法来独立地检测光自旋或轨道角动量，但是同时确定它们两者仍然是一个挑战。在这里，基于位于半环形阵列中的正交纳米狭缝对，我们设计了一个片上同时光自旋和轨道角动量检测器，它可以在对光角动量敏感的不同位置产生焦点，因此自旋和轨道角动量可以确定不雅光线。证实了可以同时高精度地确定±1的自旋角动量和宽检测范围内的轨道角动量。此外，还可以区分具有多个自旋和轨道角动量的混合光。因此，所提出的检测器提供了一种确定纳米级光角动量的方法，并且可以将来应用于片上光子学和等离激元学领域。