Magnetic Resonance

David S. Simon

Pedro José Pizarro, D. P. Weitekamp

We have recently proposed internally resonant ion cyclotron excitation (IRICE) as a tool for detecting the magnetic resonance (MR) spectra of trapped ions. A magnetic field gradient modulated at both the Larmor and cyclotron frequencies leads to cyclotron acceleration proportional to the transverse magnetic moment of a coherent state of the particle and radiation field. In the presence of a magnetic bottle, the resulting shift in the axial trapping frequency due to this spin-dependent work can be made much larger than the shift due directly to a spin flip. Our original proposal, however, was effective only for fields sharply resonant with the Larmor frequency, limiting its applicability primarily to cw MR experiments. For Fourier transform experiments, excitation of ion motion over the entire MR spectral width is desirable. FT experiments would require a large IRICE Larmor bandwidth. We present a spin-locked version of IRICE (SL-IRICE), where an additional magnetic field at the Larmor frequency is used to lock the transverse magnetic moment in phase with the IRICE field gradient. Illustrative experimental designs indicate that spectral widths sufficient for FT NMR experiments are practical. In the proposed experiment, the time evolution from a period of high-resolution precession modulates the probability ofmore » a net axial frequency shift between two detection periods. Quantum and semiclassical analyses of the excitation process agree quantitatively. Simulated signals including estimated noise illustrate the feasibility of the method.« less

Kiyoshi Ishikawa, Satoshi Morii, Katsunari Enomoto +1 more

We perform optical magnetic-resonance (MR) imaging of Cs atoms that are polarized by the transfer from the polarized Xe or Rb atoms in a glass cell as well as by direct optical pumping. With MR images of Cs by alternate optical pumping and detection the distribution of polarized Xe or Rb of low gas pressure is observed in a weak magnetic field. We also discuss the effect of the spin-relaxation and the spin-exchange collisions between Cs, Xe, and Rb atoms on the spatial resolution of MR images of the diffusing Cs atoms.

William T. Dixon

Jonathan R. J. Yong

Mingcheng Cai, Zhongzhi Guo, Fazhan Shi +5 more

We develop a parallel optically detected magnetic resonance (PODMR) spectrometer to address, manipulate, and read out an array of single nitrogen-vacancy (NV) centers in diamond in parallel. In this spectrometer, we use an array of micro-lenses to generate a 20 × 20 laser-spot lattice (LSL) on the objective focal plane and then align the LSL with an array of single NV centers. The quantum states of NV centers are manipulated by a uniform microwave field from a Ω-shape coplanar coil. As an experimental demonstration, we observe 80 NV centers in the field of view. Among them, magnetic resonance (MR) spectra and Rabi oscillations of 18 NV centers along the external magnetic field are measured in parallel. These results can be directly used to realize parallel quantum sensing and multiple times speedup compared with the confocal technique. Regarding the nanoscale MR technique, PODMR will be crucial for a high throughput single molecular MR spectrum and imaging.