We demonstrate dispersive readout of the spin of an ensemble of nitrogen-vacancy centers in a high-quality dielectric microwave resonator at room temperature. The spin state is inferred from the reflection phase of a microwave signal probing the resonator. Time-dependent tracking of the spin state is demonstrated, and is employed to measure the T ₁ relaxation time of the spin ensemble. Dispersive readout provides a microwave interface to solid state spins, translating a spin signal into a microwave phase shift. We estimate that its sensitivity can outperform optical readout schemes, owing to the high accuracy achievable in a measurement of phase. The scheme is moreover applicable to optically inactive spin defects and it is non-destructive, which renders it insensitive to several systematic errors of optical readout and enables the use of quantum feedback.

我们展示了在室温下高质量介电微波谐振器中氮空位中心集合的自旋的色散读数。自旋状态是从探测谐振器的微波信号的反射相位推断出来的。证明了自旋状态的时间相关跟踪，并用于测量T ₁自旋系综的弛豫时间。色散读数为固态自旋提供微波接口，将自旋信号转换为微波相移。我们估计它的灵敏度可以胜过光学读出方案，因为在相位测量中可以实现高精度。此外，该方案适用于光学非活性自旋缺陷，并且是非破坏性的，这使其对光学读出的几个系统误差不敏感，并能够使用量子反馈。