GaSb /GaAs quantum rings as single photon sources

量子技术利用量子力学描述的自然奇异特性，提供前所未有的速度、精度或全新功能的设备，这些设备目前根本不存在。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。有几种不同的物理系统被用来产生单光子，但很少有适合商业生产的。理想的单光子源（SPS）应该快速、廉价、在室温下运行，并且发射的光子波长与现有光纤电信网络中使用的波长相同。一个实用的SPS预计将非常类似于一种称为垂直腔面发射激光器（VCSEL）的半导体激光二极管。我们将通过开发新的VCSEL器件来评估大规模生产低成本SPSs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。

Quantum technologies exploit the exotic properties of nature described by quantum mechanics to deliver devices with unprecedented speed, accuracy or completely 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 quantum cryptography relies on the ability to generate single photons of light on demand. Several different physical systems have been used to generate single photons, but very few of them are suitable for commercial production. An ideal single photon source (SPS) should be fast, cheap, operate at room temperature, and emit photons at the wavelengths used in existing optical-fibre telecoms networks. A practical SPS is expected to be very like a type of semiconductor laser diode called a vertical cavity surface emitting laser (VCSEL). We will assess the feasibility of mass-producing low-cost SPSs by developing novel VCSEL devices whose active regions incorporate semiconductor nanostructures called self-assembled quantum rings.