标题： 密集介质中单个核自旋的腔增强光谱学 显示英文标题

标题： Cavity-enhanced spectroscopy of individual nuclear spins in a dense bath

摘要： 基于回波的光谱学能够详细洞察固体中电子自旋与其周围核自旋的超超精细相互作用的微观磁环境。尽管如此，解析密集溶液中单个核自旋仍然是一个巨大的挑战，在这些溶液中，许多核自旋表现出相当的耦合强度。 这同时要求具有高光谱分辨率和大的信噪比。 然而，在探测自旋系综时，掺杂剂之间的偶极相互作用会导致分辨率和信号之间依赖浓度的权衡。 在这里，我们通过将发射器集成到高精细度谐振腔中，完全消除了先前光学回波包络调制光谱实验的这一限制，这使得即使在非常低的浓度下也能产生强光学回波。 为了展示该技术的潜力，将其应用于钇硅酸盐（Er:YSO）中的铒掺杂剂。 实现前所未有的光谱分辨率，使精确测量与每个发射器周围密集排列的四个Y核自旋的超超精细相互作用成为可能。 由谐振腔带来的信号增强，允许将这种方法扩展到尽可能低的浓度——达到单个掺杂剂的水平，从而提供了一种检测和研究单个核自旋的工具。 因此，我们的技术为改进对固体中密集核自旋浴的理解铺平了道路。 显示英文摘要

摘要： Echo-based spectroscopy of the superhyperfine interaction of an electronic spin with nuclear spins in its surroundings enables detailed insights into the microscopic magnetic environment of spins in solids. Still, it is an outstanding challenge to resolve individual nuclear spins in a dense bath, in which many of them exhibit a comparable coupling strength. This simultaneously requires a high spectral resolution and a large signal-to-noise ratio. However, when probing spin ensembles, dipolar interactions between the dopants can lead to a concentration-dependent trade-off between resolution and signal. Here, we fully eliminate this limitation of previous optical-echo-envelope-modulation spectroscopy experiments by integrating the emitters into a high-finesse resonator, which allows for strong optical echoes even at very low concentrations. To demonstrate its potential, the technique is applied to erbium dopants in yttrium-orthosilicate (Er:YSO). Achieving an unprecedented spectral resolution enables precise measurements of the superhyperfine interaction with four of the Y nuclear spins densely surrounding each emitter. The achieved boost of the signal, enabled by the resonator, allows for extending the approach to the lowest concentration possible -- to the level of single dopants, thereby providing a tool for detecting and studying individual nuclear spins. Thus, our technique paves the way for an improved understanding of dense nuclear spin baths in solids.