Fibre wavelength quantum light sources

剑桥团队将为量子通信开发量子点单光子发射器。整个项目将演示从波长为1.55微米的LED结构中控制纠缠光子的发射。这个波长是光纤通信的标准波长。在这种波长下工作的设备将需要实现商业上重要的量子通信技术。然而，这种波长的量子点纠缠光子尚未被证明，并且在发展这种技术时存在显着的外延挑战。剑桥团队将通过分子束外延（MBE）开发在磷化铟衬底上生长的砷化铟量子点，与谢菲尔德的金属有机气相外延（MOVPE）的开发形成互补和对比。为了证明单光子发射器在这个波长是具有挑战性的，有必要通过两种技术来研究量子点的特性，以了解量子点是如何形成的，以及是什么控制了将产生光子纠缠的基本特性；包括激子自旋分裂值等方面。这项工作将在先前在谢菲尔德、东芝和卡文迪什实验室使用不同材料系统进行的波长较短的工作的基础上取得重大进展。特别是在谢菲尔德，在EPSRC项目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相似。该波长的高质量设备的演示将是将量子通信与当前非量子光纤通信基础设施相匹配的重要里程碑。

The Cambridge team will develop quantum dot single photon emitters for Quantum Communications. The overall projectaims are to demonstrate the controlled emission of entangled photons from an LED structure emitting at a wavelength of1.55microns. This wavelength is the standard wavelength for fibre communications. Devices operating at this wavelengthwill be required to achieve commercially significant Quantum Communications technologies. However entangled photonsfrom quantum dots at this wavelength have not been demonstrated and there is a significant epitaxy challenge indeveloping this technology.The Cambridge team will develop Indium Arsenide quantum dots grown on Indium Phosphide substrates by MolecularBeam Epitaxy (MBE), complementing and contrasting with the development by Metal Organic Vapour Phase Epitaxy(MOVPE) in Sheffield. To demonstrate single photon emitters at this wavelength is challenging and there is a need toinvestigate the properties of the quantum dots by both techniques to understand how the quantum dots form and whatcontrols the fundamental properties that will generate photon entanglement; including aspects such as the exciton spinsplitting value. The work will build significantly on the prior work carried out at shorter wavelengths in Sheffield, Toshibaand Cavendish laboratories using a different material system. In particular at Sheffield the result of quantum dot structuresdeveloped under an EPSRC Programme Grant will benefit the project strongly since many of the physical properties maybe similar. The demonstration of high quality devices at this wavelength will be a significant milestone in matching QuantumCommunications to the current non-quantum fibre-communications infrastructure.