Fibre Wavelength Quantum Light Sources

谢菲尔德团队和国家III-V技术中心将为量子通信开发量子点单光子发射器。整个项目的目的是展示受控发射的纠缠光子从一个LED结构发射在一个光纤兼容的波长。在这种波长下工作的设备将被要求实现商业上重要的量子通信技术。通过金属有机气相外延（MOVPE）在这些波长下开发这项技术是一个重大的外延挑战，迄今为止还没有纠缠LED的演示。谢菲尔德团队将通过MOVPE在磷化铟量子点上开发砷化铟，与卡文迪什实验室的分子束外延（MBE）方法的开发形成互补和对比。要证明这些波长的单光子发射器是具有挑战性的，并且需要通过两种技术来研究量子点的性质，以了解量子点如何形成以及是什么控制了将产生光子纠缠的基本性质;包括激子自旋分裂值等方面。这项工作将建立在谢菲尔德，东芝和卡文迪什实验室使用不同的材料系统在较短波长下进行的先前工作的基础上。特别是在谢菲尔德，在EPSRC计划资助下开发的量子点结构的结果将使该项目受益匪浅，因为许多物理性质可能是相似的。该波长的高质量设备的演示将是将量子通信与当前的非量子光纤通信基础设施相匹配的重要里程碑。

The Sheffield team and the National Centre for III-V technologies will develop quantum dot single photon emitters forQuantum Communications. The overall project aims are to demonstrate the controlled emission of entangled photons froman LED structure emitting at a fibre-compatible wavelengths. Devices operating at this wavelength will be required toachieve commercially significant Quantum Communications technologies. There is a significant epitaxy challenge indeveloping this technology by Metal Organic Vapour Phase Epitaxy (MOVPE) at these wavelengths and there have beenno demonstrations of entangled LEDs to date.The Sheffield team will develop Indium Arsenide on Indium Phosphide quantum dots by MOVPE , complementing andcontrasting with the development by the Molecular Beam Epitaxy (MBE) method in the Cavendish laboratory. Todemonstrate single photon emitters at these wavelengths is challenging and there is a need to investigate the properties ofthe quantum dots by both techniques to understand how the quantum dots form and what controls the fundamentalproperties that will generate photon entanglement; including aspects such as the exciton spin splitting value. The work willbuild significantly on the prior work carried out at shorter wavelengths in Sheffield, Toshiba and Cavendish laboratoriesusing a different material system. In particular at Sheffield the result of quantum dot structures developed under an EPSRCProgramme Grant will benefit the project strongly since many of the physical properties may be similar. The demonstrationof high quality devices at this wavelength will be a significant milestone in matching Quantum Communications to thecurrent non-quantum fibre-communications infrastructure.