Dixon Jefferson, Lawrence Mark, Barton David R, Dionne Jennifer
Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
Phys Rev Lett. 2021 Mar 26;126(12):123201. doi: 10.1103/PhysRevLett.126.123201.
The light sources that power photonic networks are small and scalable, but they also require the incorporation of optical isolators that allow light to pass in one direction only, protecting the light source from damaging backreflections. Unfortunately, the size and complex integration of optical isolators makes small-scale and densely integrated photonic networks infeasible. Here, we overcome this limitation by designing a single device that operates both as a coherent light source and as its own optical isolator. Our design relies on high-quality-factor dielectric metasurfaces that exhibit intrinsic chirality. By carefully manipulating the geometry of the constituent silicon metaatoms, we design three-dimensionally chiral modes that act as optical spin-dependent filters. Using spin-polarized Raman scattering together with our chiral metacavity, we demonstrate Raman lasing in the forward direction, while the lasing action is suppressed by over an order of magnitude for reflected light. Our high-Q chiral metasurface design presents a new approach toward compactly isolating integrated light sources by directly tailoring the emission properties of the light source itself.
为光子网络提供动力的光源体积小且可扩展，但它们也需要集成光学隔离器，这种隔离器只允许光沿一个方向通过，保护光源免受有害背反射的损害。不幸的是，光学隔离器的尺寸和复杂集成使得小规模和密集集成的光子网络无法实现。在此，我们通过设计一种既能作为相干光源又能作为其自身光学隔离器的单一器件来克服这一限制。我们的设计依赖于具有固有手性的高品质因子介电超表面。通过仔细操控组成硅超原子的几何形状，我们设计出三维手性模式，这些模式可作为光学自旋依赖滤波器。利用自旋极化拉曼散射以及我们的手性元腔，我们展示了正向的拉曼激光发射，而反射光的激光作用被抑制了一个数量级以上。我们的高Q值手性超表面设计通过直接调整光源本身的发射特性，为紧凑隔离集成光源提供了一种新方法。
