Single-Atom Trapping with Optical Tweezers for Deterministic Loading of Optical Cavities

有效的单原子单光子界面对于量子信息处理中的许多应用是必不可少的。这种混合系统的单光子传输和分布式纠缠的潜力已被证明使用87 Rb原子随机加载到一个高精细光学腔，以实现强耦合[？].虽然这个源构成了一个很好的测试平台，但概率加载限制了其设计的可扩展性，并产生了与时间相关的耦合强度。解决办法是在一个紧密聚焦的偶极阱中捕获并保持一个原子。]，一种依赖于碰撞封锁效应的技术。然而，在碰撞封锁制度的单原子占领的时间平均概率被限制为0.5 [？].在这项工作中，我们证明，增加的静态，光学偶极陷阱的深度，使过渡从快速加载（ata率为0.32 s-1）的长寿命捕获（平均寿命为8.2 s）的成功率为98%。这意味着可实现的填充比为0.72。这种将单个原子固定在适当位置的确定性方法是实现可扩展的原子-光子量子界面所需的确定性腔加载方案的重要一步。

Efficient single-atom single-photon interfaces are essential to many applications in quantum information processing. The potential of such hybridsystems for the delivery of single photons and distributed entanglement has been demonstrated using 87Rb atoms stochastically loaded into a high-finesse optical cavity to achieve strong coupling [? ]. Whilst this source constitutes an excellent testbed, probabilistic loading limits the scalability of its design and gives rise to time-dependent coupling strengths. The solution is to trap and hold a single atom in a tightly focused dipole trap [? ], a technique that relies on the collisional blockade effect. However, the time-averaged probability of single atom occupation in the collisional blockade regime is limited to 0.5 [? ]. In this work, we demonstrate that increasing the depth of a static, optical dipole trap enables the transition from fast loading (ata rate of 0.32 s-1) to long-lifetime trapping (average lifetime of 8.2 s) witha success rate of 98%. This translates to an achievable filling ratio of 0.72. Such a deterministic means of holding a single atom in place is an important step towards the deterministic cavity loading scheme required for a scalable atom-photon quantum interface.