Near-Ground-State Cooling of Atoms Optically Trapped 300 nm Away from a Hot Surface
Near-Ground-State Cooling of Atoms Optically Trapped 300 nm Away from a Hot Surface
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DOI：
10.1103/physrevx.8.031054
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发表时间：
2018-09-04
影响因子：
12.5
通讯作者：
Rauschenbeutel, A.
中科院分区：
文献类型：
--
作者：
Meng, Y.;Dareau, A.;Rauschenbeutel, A.
与纳米光子结构耦合的激光冷却原子构成了探索光与物质相互作用新机制的强大研究平台。虽然这些系统中原子内部自由度的初始化已经实现，但原子量子态的完全准备还需要在量子水平上控制原子的质心运动。获得这样的控制并不简单，因为在环境温度下原子与光子系统非常接近。在这里，我们展示了冷却的个别中性铯原子，光学接口与光在光学晶体，准备他们接近他们的三维运动基态。原子被定位在距离热纤维表面小于300 nm处。通过简并拉曼冷却实现基态制备，并通过分析外差荧光光谱信号推断原子温度。我们的冷却方法可以通过外部施加或引导光场来实现。此外，它依赖于偏振梯度，这自然会发生强烈限制的引导光场。因此，该方法可以在基于纳米光子结构的任何阱中实现。我们的研究结果提供了一个理想的起点，如光诱导自组织，测量新的光学力，并在纳米尺度上使用量子探针的热传递的调查研究的新效果。
Laser-cooled atoms coupled to nanophotonic structures constitute a powerful research platform for the exploration of new regimes of light-matter interaction. While the initialization of the atomic internal degrees of freedom in these systems has been achieved, a full preparation of the atomic quantum state also requires controlling the center-of-mass motion of the atoms at the quantum level. Obtaining such control is not straightforward because of the close vicinity of the atoms to the photonic system at ambient temperature. Here, we demonstrate cooling of individual neutral cesium atoms that are optically interfaced with light in an optical nanofiber, preparing them close to their three-dimensional motional ground state. The atoms are localized less than 300 nm away from the hot fiber surface. Ground-state preparation is achieved by performing degenerate Raman cooling, and the atomic temperature is inferred from the analysis of heterodyne fluorescence spectroscopy signals. Our cooling method can be implemented either with externally applied or guided light fields. Moreover, it relies on polarization gradients, which naturally occur for strongly confined guided optical fields. Thus, this method can be implemented in any trap based on nanophotonic structures. Our results provide an ideal starting point for the study of novel effects such as light-induced self-organization, the measurement of novel optical forces, and the investigation of heat transfer at the nanoscale using quantum probes.