Color centers in silicon have recently gained considerable attention as single-photon sources and as spin qubit-photon interfaces. However, one of the major bottlenecks to the application of silicon color centers is their low overall brightness due to a relatively slow emission rate and poor light extraction from silicon. Here, we increase the photon collection efficiency from an ensemble of a particular kind of color center, known as W centers, by embedding them in circular Bragg grating cavities resonant with their zero-phonon-line emission. We observe a ≈5-fold enhancement in the photon collection efficiency (the fraction of photons extracted from the sample and coupled into a single-mode fiber), corresponding to an estimated ≈11-fold enhancement in the photon extraction efficiency (the fraction of photons collected by the first lens above the sample). For these cavities, we observe lifetime reduction by a factor of ≈ 1.3 ${\approx} 1.3$ . For W centers in resonant bowtie-shaped cavities, we observed a ≈3-fold enhancement in the photon collection efficiency, corresponding to a ≈6-fold enhancement in the photon extraction efficiency, and observed a lifetime reduction factor of ≈ 1.1 ${\approx} 1.1$ . The bowtie cavities thus preserve photon collection efficiency and Purcell enhancement comparable to circular cavities while providing the potential for utilizing in-plane excitation methods to develop a compact on-chip light source.

中文翻译：

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来自圆形和领结布拉格光栅腔中 W 色心集合的增强零声子线发射


硅中的色心最近作为单光子源和自旋量子比特-光子界面受到了相当大的关注。然而，硅色色中心应用的主要瓶颈之一是由于发射速率相对较慢且硅的光提取能力差，其整体亮度较低。在这里，我们通过将特定类型的色心（称为 W 色心）的集合嵌入与零声线发射共振的圆形布拉格光栅腔中，提高了光子收集效率。我们观察到光子收集效率（从样品中提取并耦合到单模光纤中的光子分数）提高了 ≈5 倍），对应于光子提取效率（样品上方第一个透镜收集的光子分数）估计提高了 ≈11 倍）。对于这些空腔，我们观察到寿命缩短了 ≈ 1.3 ${\approx} 1.3$ 的倍数。对于谐振蝴蝶结形腔中的 W 色心，我们观察到光子收集效率提高了 ≈3 倍，对应于光子提取效率提高了 ≈6 倍，并观察到寿命降低因子≈ 1.1 ${\approx} 1.1$。因此，蝴蝶结腔保持了光子收集效率和与圆形腔相当的 Purcell 增强，同时为利用面内激发方法开发紧凑的片上光源提供了潜力。