Dominic Hunter, Marcin Mrozowski, Allan McWilliam, Stuart Ingleby, Terry Dyer, Paul Griffin, Erling Riis
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引用次数: 0
Abstract
Spin preparation prior to a free-induction-decay (FID) measurement can be adversely affected by transverse bias fields, particularly in the geophysical field range. A strategy that enhances the spin polarization accumulated before readout is demonstrated, by synchronizing optical pumping with a magnetic field pulse that supersedes any transverse fields by over two orders of magnitude. The pulsed magnetic field is generated along the optical pumping axis using a compact electromagnetic coil pair encompassing a micro-electromechanical systems (MEMS) vapor cell. The coils also resistively heat the cesium vapor to the optimal atomic density without spurious magnetic field contributions as they are rapidly demagnetized to approximately zero field during spin readout. The demagnetization process is analyzed electronically, and directly with a FID measurement, to confirm that the residual magnetic field is minimal during detection. The sensitivity performance of this technique is compared to existing optical pumping modalities across a wide magnetic field range. A noise floor sensitivity of 238fT/Hz was achieved in a field of approximately 50 µT, in close agreement with the Cramér–Rao lower bound predicted noise density of 258fT/Hz.
自由电感衰减(FID)测量前的自旋制备会受到横向偏置场的不利影响,特别是在地球物理场范围内。一种策略,提高自旋极化积累前读出演示,通过同步光泵浦与磁场脉冲,取代任何横向场超过两个数量级。脉冲磁场沿光泵浦轴产生,使用紧凑的电磁线圈对包围微机电系统(MEMS)蒸气池。线圈也电阻加热铯蒸气到最佳的原子密度,没有虚假的磁场贡献,因为它们在自旋读出期间迅速退磁到大约为零的场。消磁过程通过电子方式进行分析,并直接使用FID测量,以确认在检测过程中残余磁场最小。将该技术的灵敏度性能与现有的光泵浦方式在宽磁场范围内进行了比较。在大约50µT的场域中,噪声底灵敏度达到238fT/Hz,与cram r - rao下限预测的258fT/Hz噪声密度密切一致。
期刊介绍:
The Journal of the Optical Society of America B (JOSA B) is a general optics research journal that complements JOSA A. It emphasizes scientific research on the fundamentals of the interaction of light with matter such as quantum optics, nonlinear optics, and laser physics. Topics include:
Advanced Instrumentation and Measurements
Fiber Optics and Fiber Lasers
Lasers and Other Light Sources from THz to XUV
Light-Induced Phenomena
Nonlinear and High Field Optics
Optical Materials
Optics Modes and Structured Light
Optomechanics
Metamaterials
Nanomaterials
Photonics and Semiconductor Optics
Physical Optics
Plasmonics
Quantum Optics and Entanglement
Quantum Key Distribution
Spectroscopy and Atomic or Molecular Optics
Superresolution and Advanced Imaging
Surface Optics
Ultrafast Optical Phenomena
Wave Guiding and Optical Confinement
JOSA B considers original research articles, feature issue contributions, invited reviews and tutorials, and comments on published articles.