An advanced Platform for INtegrated Quantum photonics devices (PINQ)

量子信息科学是研究量子系统中存在的信息的研究领域。它为了解尚未探索的基本物理机制和开发新技术开辟了道路，这些新技术将深刻改变我们交流和处理数据的方式。事实上，由于精致的量子现象，许多新的技术应用是可以预见的。虽然经典的信息编码依赖于比特，比特可以是0或1，但量子比特(或量子比特)与量子对象的状态相关联，例如单原子、单自旋或单光子。由于量子叠加原理，量子比特可以是0、1或两者的相干叠加，从而获得异常丰富的字母表。量子信息科学还利用量子纠缠(即量子对象之间的强关联)作为快速安全的量子通信协议的资源。从实现量子通信网络的角度来看，量子存储器是基本的设备，因为它们充当光子(用作信息载体(或飞行量子比特))和静止量子比特(用于信息存储和处理)之间的接口。虽然原子气体使第一次非凡的量子存储实验成为可能，但固态系统，特别是稀土离子掺杂晶体，也提供了有趣的前景，这要归功于没有原子运动和高密度，以及它们释放了集成的前景，这有助于在现实生活中的量子技术演示中的可扩展性和可使用性。事实上，在小芯片上实现量子信息协议具有复制现代电子小型化革命的潜力，人们确实致力于开发用于量子信息处理的小型化光子集成电路。然而，未来量子通信技术的关键组件--单光子芯片上的存储器目前还没有。本奖学金通过开发基于稀土离子掺杂晶体的超快激光微加工的波导型量子存储器来解决这一紧迫的挑战。我们将为集成量子存储器设计必要的工具包，以同时满足其在现实生活中的量子网络中使用的所有要求，如按需读出、高效率、长存储时间和多模。此外，我们还将演示集成设计如何提供批量设备无法实现的功能，如单光子无损检测。这一愿景代表着在实现复杂存储器增强型量子光子学芯片电路方面的技术突破。

Quantum information science is the field of research that studies the information present in a quantum system. It opens the way to the knowledge of unexplored fundamental physical mechanisms and to the development of novel technologies that will profoundly transform the way we communicate and process our data. Indeed, a number of new technological applications can be envisaged thanks to exquisitely quantum phenomena. While classical information encoding relies on bits, which can be either 0s or 1s, the quantum bits (or qubits) are associated to the state of quantum objects, e.g., single atoms, single spins, or single photons. Because of the quantum superposition principle, the qubits can then be 0s, 1s, or coherent superposition of both, thus giving access to an exceptionally richer alphabet. Quantum information science also exploits quantum entanglement, i.e., strong correlation between quantum objects, as a resource for fast and secure quantum communication protocols.In view of realizing networks for quantum communication, quantum memories are fundamental devices as they act as interfaces between the photons, used as information carriers (or flying qubits), and stationary qubits, exploited for information storage and processing. While atomic gases enabled the first remarkable quantum storage experiments, solid-state systems, and specifically rare earth ion doped crystals, also offer interesting perspectives thanks to the absence of atomic motion and the high density, and the fact that they unleash prospects of integration, which facilitates scalability and employability in real-life quantum technology demonstrations. As a matter of fact, the implementation of quantum information protocols on a small chip has the potential to replicate the revolution of modern electronic miniaturization and intense research efforts are indeed devoted to developing miniaturized photonic integrated circuits for quantum information processing. Yet, on chip memories for single photons, key components of future quantum communication technology, are currently missing. This Fellowship addresses this pressing challenge by developing waveguide quantum memories based on ultrafast laser micromachining of rare earth ion doped crystals. We will engineer the necessary tool kit for the integrated quantum memories to fulfil simultaneously all the requirements for their employability in real-life quantum networks, as on-demand read-out, high efficiency, long storage time, and multimodality. Moreover, we will demonstrate how the integrated design gives access to functionalities that are not possible with bulk devices, like the non-destructive detection of single photons. This vision represents a technological breakthrough toward the realization of complex memory-enhanced quantum photonics circuitry on chip.