GaSb/GaAs quantum rings as single photon sources

量子技术是利用量子力学描述的自然奇异特性，以前所未有的速度和精度提供与传统技术相比的设备，甚至产生具有新功能的全新技术，这些技术目前根本不存在。量子密码学就是这样一种通信技术，其安全性由量子力学的基本定律保证。量子密码学的实现依赖于按需产生单光子的能力。几种不同的物理系统已经被用来产生单光子，但很少有适合商业生产的，因为它们不切实际且不方便。理想的单光子源应该快速、廉价、在室温下工作，并且发射的光子波长与现有的基于光纤的电信系统相同。事实上，一种实用的单光子源预计看起来很像一种半导体激光二极管，称为垂直腔面发射激光器（VCSEL）。在这个为期一年的项目中，我们将通过开发新型VCSEL器件来评估大规模生产具有电信波长发射的低成本室温单光子源的可行性，该器件的有源区域包含称为自组装量子环的半导体纳米结构。这将使我们在实际的，即商业的单光子源的发展中跨越一个阶段，并对其商业潜力进行现实的评估。

Quantum technologies are those which exploit the exotic properties of nature described by quantum mechanics to deliverdevices with unprecedented speed or accuracy compared with conventional technology, or even generate completely noveltechnologies with new functionalities, which simply do not exist at present. Quantum cryptography is one such technology:communication whose security is guaranteed by fundamental laws of quantum mechanics. The implementation of quantumcryptography relies on the ability to generate single photons of light on demand. Several different physical systems havebeen used to generate single photons, but very few of them are suitable for commercial production as they are impracticaland inconvenient. An ideal single photon source should be fast, cheap, operate at room temperature, and emit photons atthe wavelengths used in existing optical-fibre based telecommunications systems. In fact, a practical single photon sourceis expected to look very like a type of semiconductor laser diode called a vertical cavity surface emitting laser (VCSEL). Inthis year-long project we will assess the feasibility of mass-producing low-cost, room-temperature single photon sourceswith telecom-wavelength emission by developing novel VCSEL devices whose active regions incorporate tinysemiconductor nanostructures called self-assembled quantum rings. This will allow us to leap-frog a stage in thedevelopment of practical, i.e. commercial, single photon sources, and to make a realistic assessment of their commercialpotential.