Heterogenous quantum systems for single photon delay and pulse shaping (HQSys)

光子量子技术是一个令人兴奋的科学技术领域。潜在的应用包括安全量子通信、量子计算和长期的量子互联网。它们有一个共同点，那就是信息被编码在充当飞行量子比特的单个光子中。重要的是，这些飞行的量子比特需要与静止的量子比特有效地接口，以实现量子存储器和量子门。该项目的主要目标是开发和测试用于存储和检索以及有效处理单个量子点光子的光谱/时间波形的量子存储器。我们的项目首次实现了半导体量子点与碱性原子中实现的量子存储器之间的异质量子界面。量子纳米光子学中的这一关键构件使量子中继器协议中几乎完全无法区分的光子和接近单位的纠缠交换保真度得以产生。同时，我们设想量子信息可以被编码到单个光子的时间包络和相位中，从而实现大容量的量子信息传输。潜在的技术途径是将半导体量子点中高效的按需光子产生与在热原子蒸气中实现的量子存储相结合。该源是通过单量子点CBR器件的电子束原位光刻确定实现的。在这里，先进的原位EBL纳米技术平台为制备发射波长可控、光子提取效率高的量子光源提供了保证。该存储器在热Cs蒸气中遵循快速梯形EIT方案。

Photonic quantum technology is an exciting field in science and technology. Potential applications include secure quantum communication, quantum computing and on the long-term the Quantum Internet. These have in common that information is encoded in single photons acting as flying qubits. Importantly, these flying qubits need to be efficiently interfaced with stationary qubits to implement quantum memories and quantum gates. The overarching goal of this project is to develop and test a quantum memory for the storage and retrieval as well as for the efficient spectral/temporal waveform manipulation of single quantum dot photons. Our project realizes for the first time a heterogeneous quantum interface between semiconductor quantum dots and a quantum memory realized in alkaline atoms. This key building block in quantum nanophotonics enables the generation of almost perfectly indistinguishable photons and near unity entanglement swapping fidelity in quantum repeater protocols. At the same time, we envision that quantum information can be encoded into the temporal envelope and phase of the single photons allowing for high capacity quantum information transfer with large alphabet.The underlying technological approach is to combine the efficient and on-demand photon generation in semiconductor quantum dots with quantum memories implemented in warm atomic vapor. The source is realized deterministically by in-situ electron beam lithography of single-QD CBR devices. Here, the advanced in-situ EBL nanotechnology platform guarantees the fabrication of QD quantum light source with well-controlled emission wavelength and high photon extraction efficiency. The memory follows a fast ladder EIT scheme in warm Cs vapor.