Controlling coherent interaction between optical fields and quantum systems in scalable, integrated platforms is essential for quantum technologies. Miniaturised, warm alkali-vapour cells integrated with on-chip photonic devices represent an attractive system, in particular for delay or storage of a single-photon quantum state. Hollow-core fibres or planar waveguides are widely used to confine light over long distances enhancing light-matter interaction in atomic-vapour cells. However, they suffer from inefficient filling times, enhanced dephasing for atoms near the surfaces, and limited light-matter overlap. We report here on the observation of modified electromagnetically induced transparency for a non-diffractive beam of light in an on-chip, laterally-accessible hollow-core light cage. Atomic layer deposition of an alumina nanofilm onto the light-cage structure was utilised to precisely tune the high-transmission spectral region of the light-cage mode to the operation wavelength of the atomic transition, while additionally protecting the polymer against the corrosive alkali vapour. The experiments show strong, coherent light-matter coupling over lengths substantially exceeding the Rayleigh range. Additionally, the stable non-degrading performance and extreme versatility of the light cage provide an excellent basis for a manifold of quantum-storage and quantum-nonlinear applications, highlighting it as a compelling candidate for all-on-chip, integrable, low-cost, vapour-based photon delay.

在可扩展的集成平台中控制光场和量子系统之间的相干相互作用对于量子技术至关重要。与片上光子器件集成的小型化、温暖的碱蒸汽电池代表了一个有吸引力的系统，特别是对于单光子量子态的延迟或存储。空心光纤或平面波导被广泛用于远距离限制光，从而增强原子蒸汽电池中的光与物质相互作用。然而，它们的填充时间效率低下、表面附近原子的相移增强以及光物质重叠有限。我们在此报告了对片上可横向访问的空心光笼中非衍射光束的改进电磁感应透明度的观察。利用氧化铝纳米薄膜在光笼结构上的原子层沉积，将光笼模式的高透射光谱区域精确调整为原子跃迁的工作波长，同时额外保护聚合物免受腐蚀性碱蒸汽的影响。实验表明，在大大超过瑞利范围的长度上，强的、相干的光-物质耦合。此外，光笼稳定的非降解性能和极端的多功能性为多种量子存储和量子非线性应用提供了极好的基础，突出表明它是全片上、可集成、低成本的引人注目的候选者，基于蒸气的光子延迟。