Controlling Environmental Interactions for Novel Solid-State Quantum Technologies

量子点（QDs）是半导体的纳米级区域，嵌入在更大的第二半导体主机中。这两种半导体的不同性质意味着单个电荷粒子（电子）可以被捕获在量子点中，从而允许在单个粒子水平上研究光与物质的相互作用。特别是，量子点形成了光（光子）量子态的极好来源，这是许多令人兴奋的新量子技术（如安全通信和增强传感）所必需的。固态宿主的一个结果是量子点与其局部环境相互作用，一个特别重要的例子是晶格的量子化振动，称为声子。这些相互作用通常被认为是与量子点和其他类似的固态系统一起工作的不受欢迎但不可避免的后果。本提案旨在证明，通过适当的纳米制造和控制量子点几何形状，量子点与其光学（光子）和振动（声子）环境的相互作用可以被控制。通过实现对环境相互作用的控制，声子相互作用对发射光子的影响几乎可以消除，从而提高量子点光子源的效率和质量，以支持新的应用。此外，对极低温冷却的需求可以大大减少，从而消除了量子技术应用的重大障碍。利用这些发展，基于量子点平台将开发几种新的量子技术。量子双光子显微镜提供了对精细样品进行成像的潜力，这些样品可能会被当前方法所需的强光场破坏。同时，利用声子相互作用“挤压”量子点发射的光子的不确定性，可以实现高灵敏度的光学传感。最后，量子数据锁定为量子安全通信提供了潜力，其效率比现有方法高得多。

Quantum dots (QDs) are nanoscale regions of semiconductor, embedded within a much larger host of a second semiconductor. The differing properties of the two semiconductors mean that single particles of charge (electrons) can be trapped within a QD, allowing for study of light-matter interactions on a single particle level. In particular, QDs form an excellent source of the quantum states of light (photons) that are required for many exciting new quantum technologies such as secure communication and enhanced sensing.A consequence of the solid-state host is that the QD interacts with its local environment, a particularly important example being quantised vibrations of the lattice, termed phonons. These interactions have typically been considered an unwelcome but unavoidable consequence of working with QDs and other similar solid-state systems. This proposal aims to demonstrate that through appropriate nano-fabrication and control of the QD geometry, the interaction of the QD with both its optical (photonic) and vibrational (phononic) environments can be controlled. By realising such control over environmental interactions, the impact of phonon interactions on the photons emitted can be almost eliminated, increasing the efficiency and quality of the QD photon source to support new applications. Furthermore, the need for extreme cryogenic cooling can be greatly reduced, removing a significant barrier to quantum technologies applications.Harnessing these developments, several novel quantum technologies will be developed based on the QD platform. Quantum 2-photon microscopy offers the potential to perform imaging of delicate samples that would be damaged by the intense light fields required for current methods. Meanwhile, high sensitivity optical sensing can be realised by using phonon interactions to "squeeze" the uncertainty in photons emitted by the QD. Finally, quantum data locking offers the potential for quantum-secured communication with a significantly higher efficiency than existing methods.