A Large Bandwidth Room Temperature Single Photon Source

大带宽室温单光子源

• 批准号: 428456730
• 负责人: Dr. Robert Löw
• 金额: --
• 依托单位: Weizmann Institute of Science
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/428456730?language=en
• 关键词: Large; Bandwidth; Room; Temperature; Single

This project is dedicated to the realization of a single photon source based on strong interactions between Rydberg atoms in a thermal vapour. The possibility to produce anti-bunched photons in a gas of Rubidium atoms has been shown very recently in a proof of principle experiment by the applicants. In this experiment we have shown that, in a micron sized excitation volume, the blockade effect is sufficient to allow for only one Rydberg excitation, which can then be transferred to a light mode in a four-wave mixing scheme. This conversion has to happen within the lifetime of the strongly correlated many body state. In our excitation scheme the coherence time is limited by the motion of the atoms to roughly one nano-second. This means that sufficient strong laser pulses are required to achieve GHz Rabi-frequencies. One of the bottlenecks in our experiment is the small repetition rate (50Hz) of our laser-system. In this proposal we want to realize a second generation of the vapour based single photon source, which will be much closer to real applications. First of all, we will switch to a different four-wave mixing scheme, where we can operate the lasers at rates well above 100kHz giving much better photon statistics. Also parts of the optics will be integrated in the vapour cells as solid immersion lenses. To improve the atom-light coupling, we will also add optical coatings to produce low to medium finesse cavities. This coatings will also include protective coatings to a void chemical reactions. On the material side we will investigate how different Rydberg atoms interact with the close by walls made of Quartz, Sapphire, etc. With the new laser system we will also obtain control over the actual pulse shapes down to the 50ps scale, which will require extended numerical simulations to obtain an optimal sequence. Finally we want to prove the scalability of our approach by realizing two single photon sources in one cell and characterize the indistinguishability of the emitted photons in a Hong-Ou-Mandel interferometer.A notable part of this project will be the cooperation with Dr. Ofer Firstenberg (Weizmann Institute of Science, Israel). His group has broad expertise on Rydberg atoms as well as on the spectroscopy on thermal vapours. As both groups have a strong need for vapour cells featuring optical coatings we will develop together the fabrication of such cells.All these measures will increase the photon rate as well the fidelity of our source. One application would be a purely vapour based quantum repeater scheme, where the wavelength and the bandwidth of the single photon source and of the storage is naturally matched. Another application lies in linear quantum computation or in the creation of more complex photon states (higher Fock states, noon-states,...).

本项目致力于实现基于热蒸汽中里德伯原子之间强相互作用的单光子源。在铷原子气体中产生反束光子的可能性，在最近由申请者进行的原理证明实验中得到了证明。在这个实验中，我们已经证明，在微米大小的激发体积中，封锁效应足以允许只有一个里德堡激发，然后可以在四波混频方案中将其转移到光模式。这种转换必须在强相关多体状态的生命周期内发生。在我们的激发方案中，相干时间受到原子运动的限制，大约为1纳秒。这意味着需要足够强的激光脉冲来达到GHz的rabi频率。我们实验的瓶颈之一是我们的激光系统的重复频率很小（50Hz）。在这个提议中，我们希望实现第二代基于蒸汽的单光子源，这将更接近实际应用。首先，我们将切换到一个不同的四波混频方案，在那里我们可以以远高于100kHz的速率操作激光器，从而获得更好的光子统计。此外，部分光学元件将集成在蒸汽电池作为固体浸没透镜。为了改善原子-光耦合，我们还将添加光学涂层来产生低到中等精细度的腔。这种涂层还会包括保护涂层，使其发生化学反应。在材料方面，我们将研究不同的里德伯原子如何与由石英、蓝宝石等制成的近壁相互作用。使用新的激光系统，我们还可以将实际脉冲形状控制到50ps的范围，这将需要扩展的数值模拟来获得最佳序列。最后，我们想通过在一个单元中实现两个单光子源来证明我们方法的可扩展性，并表征了在Hong-Ou-Mandel干涉仪中发射光子的不可区分性。这个项目的一个值得注意的部分将是与奥弗·弗斯滕伯格博士（以色列魏茨曼科学研究所）的合作。他的团队在里德伯原子和热蒸汽光谱方面有着广泛的专业知识。由于两组都对具有光学涂层的蒸汽电池有强烈的需求，我们将共同开发这种电池的制造。所有这些措施都将提高光子速率和光源的保真度。一个应用将是纯基于蒸汽的量子中继器方案，其中单个光子源和存储的波长和带宽自然匹配。另一个应用是线性量子计算或创建更复杂的光子态（高Fock态，非态，…）。