Patrickson Charlie J, Haemmerli Valentin, Guo Shi, Ramsay Andrew J, Luxmoore Isaac J
Department of Engineering, University of Exeter, Exeter, UK.
Hitachi Cambridge Laboratory, Hitachi Europe Ltd., Cambridge, UK.
Nat Commun. 2025 May 12;16(1):4380. doi: 10.1038/s41467-025-59148-9.
By sequentially recording the phase of an AC signal relative to an external clock, quantum heterodyne schemes have recorded MHz and GHz signals with Fourier-limited precision. However, in systems with large inhomogeneous broadening, existing heterodyne protocols provide limited protection of the spin coherence, impacting amplitude sensitivity. Here, we use a continuous microwave scheme that extends spin coherence towards the effective limit and resolves the frequency, amplitude and phase of MHz to GHz magnetic fields. In an ensemble of boron vacancies in hexagonal boron nitride the scheme achieves an amplitude sensitivity of and phase sensitivity of . We demonstrate that the scheme is compatible with quantum heterodyne detection, recording a GHz signal with a resolution < 1 Hz and SNR of 235 over a 10 s measurement. Achieving this performance in a two-dimensional material platform could have broad applications in probing nanoscale condensed matter systems.
通过顺序记录交流信号相对于外部时钟的相位，量子外差方案已以傅里叶极限精度记录了兆赫兹和吉赫兹信号。然而，在具有大的非均匀展宽的系统中，现有的外差协议对自旋相干的保护有限，影响幅度灵敏度。在这里，我们使用一种连续微波方案，该方案将自旋相干扩展到有效极限，并解析兆赫兹到吉赫兹磁场的频率、幅度和相位。在六方氮化硼中的硼空位集合中，该方案实现了幅度灵敏度为 以及相位灵敏度为 。我们证明该方案与量子外差检测兼容，在 10 秒的测量中记录了分辨率 < 1 Hz 且信噪比为 235 的吉赫兹信号。在二维材料平台上实现这种性能可能在探测纳米级凝聚态物质系统方面有广泛应用。
