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

可用于固态材料的光学可寻址自旋缺陷因其用于信息处理和存储的长相干时间而有望用于可扩展的量子信息处理。此外，分布在量子网络中的单个色心可以通过光子促进的相互作用进行纠缠，这在现有的光纤基础设施中享有低损耗传播。因此，在过去的二十年里，金刚石中的氮空位(NV)中心等缺陷态受到了广泛的关注。尽管做出了这些努力，但NV中心的技术水平只成功地实现了少数几个量子节点的纠缠，这表明要实现任何实际应用，还有很多工作要做。最近，碳化硅(碳化硅)作为另一种很有前途的量子材料出现，因为它在包括3C，4H和6H在内的多型体中含有多种色心。与金刚石中的NV中心相比，由于碳化硅是一种具有良好的电学和光学性能的兼容材料，所以碳化硅中的本征缺陷表现出类似的自旋性质，同时具有独特的集成和尺度优势。这个量子制造计划的目标是开发碳化硅中基于钒的色心，这种色心可以用作电信波段的高质量单光子发射体。具体地说，通过优化离子注入，并结合各种集成光子技术，在低损耗的4H-SiC-on-绝缘体平台上确定地引入单个钒缺陷。这种色心与芯片级量子技术的单片集成具有在减少设备交换(尺寸、重量和功率)和增加芯片级别的可用功能方面改变量子信息处理的潜力。这最终将导致功能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，拟议的研究活动有望为下一代量子工程师的教育提供优秀的学习材料，研究成果将被整合到相关课程和推广计划中。该项目的成功取决于方法和技术的开发，这些方法和技术能够将钒缺陷可控地引入到低损耗的4H-碳化硅绝缘体平台上，作为高质量的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相结合并实现强相互耦合是一种成熟的技术，可以显著缩短缺陷的光学寿命并提高其发射率(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励和光谱滤波成为可能，与基于自由空间光学的方法相比，这导致了一种紧凑的系统解决方案。我们还将探索钒缺陷的电调谐(斯塔克效应)，并将普克尔斯效应应用到碳化硅微谐振器中，以实现频率调谐和高效的电光调制。如果成功，我们将开发一种工作在电信频段的紧凑型单光子发射器，具有GHz级的发射速率，通过在4H-SIC中使用紧凑型电光调制器，它可以很容易地与经典信息对接。这种高性能量子源有望在下一代量子通信中发挥关键作用。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.