Collective optical effects of ultra-cold Rydberg atoms in optical cavities

光学腔中超冷里德伯原子的集体光学效应

• 批准号: 422447846
• 负责人: Professor Dr. Sebastian Slama
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 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/422447846?language=en
• 关键词: Collective; optical; effects; ultra; cold

The project aims at studying the influence of strong intermediate-range dipole-dipole interactions of Rydberg atoms on the collective external and internal dynamics of ultracold atoms inside an optical cavity. Atoms in cavities are known to self-organize in periodic structures when they are illuminated from the side of the cavity by laser light. The self-organization process is triggered by the light which is collectively scattered into the cavity, recycled by the cavity mirrors, and mechanically back acts on the atoms. This cavity-mediated interaction between the atoms is infinite-range. New physics comes into play by the additional interactions of Rydberg atoms. At intermediate distance dipole-dipole interactions between Rydberg atoms suppress the excitation of more than one Rydberg atom, i.e. Rydberg blockade. Thus, within a Rydberg bubble light scattering is a highly nonlinear process, and scattering of light into the cavity is a collective phenomenon of the individual Rydberg bubbles rather than of the individual atoms. We will study the effect of Rydberg blockade on the emerging self-organized structures and on the intensity and phase of the light scattered into the cavity. Furthermore, we will study if the additional interaction can lead to new stable phases of the atom cloud, depending on the size of the blockade radius and of the atom cloud as a whole.The internal dynamics is governed by the fact that the cavity mode is near-resonant to the transition from the atomic ground state to an intermediate level, with collectively enhanced coupling. The intermediate state in turn is coupled to a Rydberg state by a strong external coupling laser field. For large detuning from the intermediate level, the dynamics is that of an effective two-level system, where the coupling between the atoms and the cavity is mediated by a two-photon transition. The coupling strength can thus be tuned by the intensity of the coupling laser, whereas the cavity is only resonant to the photons of the lower transition. This fact is remarkable and makes a difference to the usual case where the cavity field is resonant to a single photon transition. Using two-photon transitions the coupling strength can be externally controlled both in time and in space, which is a very interesting feature for applications in quantum technology, as for instance quantum memories. We will lay the fundament for such future applications by demonstrating strong collective coupling of cavity light and atomic two-photon transitions between the ground state and Rydberg states. This will be achieved by observing vacuum Rabi oscillations using pulsed excitation schemes.

该项目旨在研究里德堡原子的强中程偶极-偶极相互作用对光学腔内超冷原子集体外部和内部动力学的影响。已知腔中的原子在被激光从腔的侧面照射时以周期性结构自组织。自组织过程由集体散射到腔中的光触发，由腔镜回收，并机械地反向作用于原子。原子之间的这种腔介导的相互作用是无限程的。新的物理学通过里德伯原子的额外相互作用而发挥作用。在中等距离处，里德伯原子之间的偶极-偶极相互作用抑制了多个里德伯原子的激发，即里德伯阻断。因此，在里德伯泡内，光散射是一个高度非线性的过程，光散射到腔中是单个里德伯泡的集体现象，而不是单个原子的集体现象。我们将研究里德堡封锁对新兴的自组织结构和散射到腔中的光的强度和相位的影响。此外，我们将研究额外的相互作用是否会导致新的稳定相的原子云，这取决于大小的封锁半径和原子云作为一个整体。内部动力学是由这样的事实，即腔模式是近共振的原子基态过渡到一个中间的水平，集体增强耦合。中间态又通过强的外部耦合激光场耦合到里德伯态。对于从中间能级的大失谐，动力学是一个有效的两能级系统，其中原子和腔之间的耦合是由双光子跃迁介导的。因此，耦合强度可以通过耦合激光的强度来调谐，而腔仅与较低跃迁的光子共振。这一事实是显著的，并且与通常的腔场与单光子跃迁共振的情况不同。使用双光子跃迁，耦合强度可以在时间和空间上都受到外部控制，这对于量子技术中的应用（例如量子存储器）来说是一个非常有趣的特征。我们将通过展示腔光的强集体耦合和原子基态与里德伯态之间的双光子跃迁，为这种未来的应用奠定基础。这将通过使用脉冲激发方案观察真空拉比振荡来实现。