Nonlinear quantum optics using Rydberg excitons

世纪见证了量子力学的诞生，这是一种微观理论，它挑战了我们对周围世界的每一点直觉。这一发现，导致了对光，物质的性质以及它们在绝对最小尺度上的相互作用的开创性见解。随后，随着半导体和激光的发明，这催生了一个技术文明的新时代。现在，我们正处于第二次量子革命的黎明，它被认为是21世纪世纪大部分关键技术进步的原因。从几乎无法破解的通信到具有奇异特性的合成材料，量子技术构成了这些进步的共同点。虽然科学界正在推动在各种平台上实现量子硬件，但最近出现的一个突出候选者是氧化亚铜。由于其大的结合能和高的光学纯度，在天然存在的氧化亚铜样品中观察里德伯态激发是可能的。里德伯激发具有夸张的性质，如大半径和跃迁偶极矩，强极化率和长的辐射寿命，控制状态选择和应用的外部领域。这些性质导致晶体内不同激发之间的强货车范德华力，其在几微米内占主导地位。这赠款工程师的能力，空间分离的自旋和光子之间的相互作用，同时保持状态读出能力通过opticalmeans.This工作是多方面的，首先，我们将专注于合成氧化亚铜微晶的生长是高光学纯度，在现有的薄膜沉积和退火设施在牛津大学。在研究合成晶体生长的同时，还将努力设计和组装一个在低温下运行的全光学实验，这将是主要的表征站。样品的表征将通过采用基于反射的光致发光光谱，在零和有限的磁场，和真实空间显微镜技术，如扫描共聚焦显微镜。光谱学将使我们能够探测合成样品的质量，而扫描共聚焦显微镜将允许构建光致发光图，并允许选择确定性地将光束引导到感兴趣的光学活性区域。此外，连续波和脉冲激光的组合将有助于定制和表征里德堡激发的自旋状态。在后期阶段，该项目将专注于单个微晶在与当前芯片制造行业标准兼容的平台上的确定性定位，并研究将该平台与电子和光子组件集成的可能性，作为实现自旋模型的片上可编程量子模拟的途径。该项目福尔斯“量子光学和信息”研究领域。

The 20th century has witnessed the birth of quantum mechanics, a microscopic theory which defied every bit of intuition regarding the world around us. This discovery, led to pioneering insights about the nature of light, matter, and their interaction at the absolute smallest scales. Subsequently, this gave birth to a new era of technological civilisation with the invention of semiconductors, and the laser. Now, we are at the dawn of a second quantum revolution, where it is thought to be responsible for most of the key technological advancements of the 21st century. From virtually unhackable communications, to synthetic materials with exotic properties, quantum technologies constitute the common denominator for these advancements.While the scientific community is pushing towards the implementation of quantum hardware on a variety of platforms, a prominent candidate that has recently emerged as a solid-state solution is the cuprous oxide. Owning to its large binding energy and high optical purity, observation of Rydberg-state excitations was possible in samples of naturally occurring cuprous oxide. Rydberg excitations possess exaggerated properties like large radii and transition dipole moments, strong polarisability and long radiative lifetimes, controlled by state selection and application of external fields. These properties lead to strong van der Waals forces between different excitations within the crystal, that dominate over several microns. This grants capability to engineer interactions between spatially separated spins and photons, while preserving state read-out capability via optical means.This work is multi-faceted, and firstly we will focus on the growth of synthetic cuprous oxide micro-crystals that are of high optical purity, at the available thin-film deposition and annealing facilities at the University of Oxford. While working on synthetic crystal growth, an effort will run in parallel to design and assemble an all-optical experiment operating at cryogenic temperatures which will be the main characterisation station. Characterisation of the samples will be made possible by employing reflection-based photoluminescence spectroscopy, both at zero and finite magnetic fields, and real-space microscopy techniques like scanning confocal microscopy. Spectroscopy will allow us to probe the quality of the synthetic samples, while scanning confocal microscopy will allow to construct photoluminescence maps and grant the option to deterministically steer the beam to optically active areas of interest. Moreover, a combination of continuous-wave and pulsed lasers will aid in tailoring and characterising the spin-state of the Rydberg excitations. At a later stage, this project will focus on the deterministic positioning of individual micro-crystals on a platform that is compatible with current chip manufacturing industry-standards and investigate the possibility of integrating this platform with electronic and photonic components, as a pathway towards on-chip programmable quantum simulation of spin models.This project falls under the "Quantum optics and information" research area.