EAGER: Quantum Manufacturing: Monolithic integration of telecommunication-band quantum emitters in the 4H-SiC-on-insulator platform

固态材料中的可光学寻址自旋缺陷由于其用于信息操作和存储的长相干时间而有希望用于可扩展的量子信息处理。此外，分布在量子网络中的各个色心可以通过光子促进相互作用纠缠在一起，这在现有的光纤基础设施中具有低损耗的传播。因此，在过去的二十年中，金刚石中的缺陷态如氮空位（NV）中心受到了很多关注。尽管做出了努力，但NV中心的最新技术水平只实现了几个量子节点的成功纠缠，这表明在任何实际应用中还有很多工作要做。最近，碳化硅（SiC）成为另一种有前途的量子材料，因为它在其多型体中拥有各种色心，包括3C，4 H和6 H。与金刚石中的NV中心相比，SiC中的本征缺陷表现出类似的自旋特性，同时具有独特的集成和缩放优势，因为SiC是具有良好电学和光学特性的CMOS兼容材料。该量子制造计划的目标是在SiC中开发钒基色心，可用作电信波段的高质量单光子发射器。具体而言，单一钒缺陷将通过优化的离子注入确定性地引入，并与各种集成的光子技术相结合，在低损耗的4 H-SiC-on-insulator平台。这种色心与芯片级量子技术的单片集成有可能在降低器件的SWaP（尺寸、重量和功率）和增加芯片级可用功能方面改变量子信息处理。这最终将导致一个强大的固态量子处理器，在未来量子网络的可扩展实现中发挥不可或缺的作用。此外，该研究项目还将为下一代量子工程师的教育提供优秀的学习材料，并将研究成果纳入相关课程和推广计划中。该项目的成功取决于开发方法和技术，使钒缺陷可控地引入低损耗4 H-SiC-on-insulator平台，作为高质量，电信波段单光子发射器。例如，将单个缺陷与高品质因数微谐振器组合并实现强互耦合是一种经验证的技术，可以显著降低缺陷的光学寿命并增强其发射速率（珀塞尔效应）。此外，波导和微谐振器等低损耗集成光子技术使片上光激发和光谱滤波成为可能，与基于自由空间光学的方法相比，这导致了紧凑的系统解决方案。我们也将探讨钒缺陷（斯塔克效应）的电调谐，并将普克尔斯效应应用于SiC微谐振器的频率调谐和有效的电光调制。如果成功的话，我们将开发一种紧凑的单光子发射器，它工作在电信频段，具有GHz级的发射率，它可以很容易地与经典的信息接口，通过采用一个紧凑的电光调制器在4 H-SiC。这种高性能的量子源有望在下一代量子通信中发挥关键作用。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Optically addressable spin defects available in solid-state materials are promising for scalable quantum information processing owing to their long coherence time for information manipulation and storage. In addition, individual color centers distributed in a quantum network can be entangled through photon facilitated interaction, which enjoys low-loss propagation in the existing fiber infrastructure. As such, defect states such as nitrogen-vacancy (NV) centers in diamond received a lot of attention in the past two decades. Despite the efforts, the state of the art of NV centers has only achieved successful entanglement of a few quantum nodes, suggesting much work to be done for any practical applications. Recently, silicon carbide (SiC) emerged as another promising quantum material, as it hosts a variety of color centers in its polytypes including 3C, 4H and 6H. Compared to NV centers in diamond, intrinsic defects in SiC exhibit similar spin properties while possessing unique integration and scaling advantages given that SiC is a CMOS-compatible material with favorable electrical and optical properties. The objective of this quantum manufacturing program is focused on the development of vanadium-based color centers in SiC that can be utilized as high-quality single-photon emitters in the telecommunication band. Specifically, single vanadium defect will be deterministically introduced through optimized ion implantation and combined with various integrated photonic technologies in a low-loss 4H-SiC-on-insulator platform. Such monolithic integration of color centers with enabling chip-scale quantum technologies has the potential to transform quantum information processing in terms of reducing the device’s SWaP (size, weight, and power) and increasing available functionalities on the chip level. This eventually will lead to a powerful solid-state quantum processor that plays an indispensable role in the scalable implementation of future quantum networks. Moreover, the proposed research activities are expected to produce excellent learning materials for the education of next-generation quantum engineers, and the research findings will be integrated into relevant courses and outreach programs.The success of the project hinges on the development of methods and technologies that enable controllable introduction of vanadium defects to a low-loss 4H-SiC-on-insulator platform as a high-quality, telecom-band single photon emitter. For example, combining a single defect with a high-quality-factor microresonator and achieving strong mutual coupling is a proven technology to significantly reduce the defect’s optical lifetime and enhance its emission rate (Purcell effect). In addition, low-loss integrated photonic technologies such as waveguides and microresonators make on-chip optical excitation and spectral filtering feasible, which leads to a compact system solution compared to approaches based on free-space optics. We will also explore the electrical tuning of the vanadium defect (Stark effect) and apply the Pockels effect to the SiC microresonator for frequency tuning and efficient electro-optic modulation. If successful, we will develop a compact single-photon emitter that works in the telecommunication band with GHz-level emission rate, which can be readily interfaced with the classical information by employing a compact electro-optic modulator in 4H-SiC. Such a high-performance quantum source is expected to play a critical role in the next-generation quantum communication.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.