Quantum control of spin centers in silicon carbide with microcavities

微腔是光子作为飞行量子比特和电子自旋作为静止量子比特之间的理想界面，因为它们强烈地增强了光与物质之间的相互作用。因此，它们是研究和操纵光、物质及其相互作用的量子力学性质的最重要工具之一。碳化硅（SiC）是一种非常有前途的材料平台，用于晶圆级自旋电子学和量子信息处理。首先，这是因为SiC是一种与CMOS（互补金属氧化物半导体）技术兼容的材料，允许在SiC晶圆上构建集成电路，就像硅一样。其次，最重要的是，这种材料中的自旋中心，特别是硅空位，已经在商业晶圆中展示了非常长的自旋相干时间，并且即使在单自旋水平上也可以进行光学控制。然而，这些中心应用的主要障碍是单中心计数率低和自旋读数对比度低。在这个项目中，我们将单个自旋色中心耦合到由SiC芯片和硅微镜组成的高质量谐振器上。这种类型的微镜提供了优良的表面质量，小的曲率半径和可扩展性的直接途径。使用共振激发和检测方案，我们计划将自旋读数对比度提高到50%以上。最后，我们计划在SiC中展示自旋光子纠缠与硅空位，这是实现量子中继器和网络的重要一步。

Microcavities are ideal interfaces between photons as flying qubits and electron spins as stationary qubits, as they strongly enhance the interaction between light and matter. They are therefore among the foremost tools in the study and manipulation of the quantum mechanical nature of light, matter and their interactions. Silicon carbide (SiC) is a very promising material platform for wafer-scale spintronics and quantum information processing. First, this is because SiC is a material compatible with CMOS (complementary metal-oxide-semiconductor) technology, allowing construction of integrated circuits on a SiC wafer, just as silicon. Second and most importantly, spin centers in this material, particularly silicon vacancies, demonstrate an exceptionally long spin coherence time already in commercial wafers and they can be optically controlled even at the single-spin level. However, the main obstacles against applications of these centers are a low count rate from single centers and a low spin readout contrast.In this project, we will couple a single spin color center to a high quality resonator formed by a SiC chip and a silicon micromirror. This type of micromirror offers excellent surface quality, small radii of curvature and a direct path to scalability. Using resonant excitation and detection schemes, we plan to increase the spin readout contrast to above 50%. Finally, we plan to demonstrate spin-photon entanglement with a silicon vacancy in SiC, which is an important step towards implementation of quantum repeaters and networks.