The Observation of Magnetic Resonance

Antoine Weis

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.

Sergei P. Dmitriev, N. A. Dovator, Victor A. Kartoshkin +1 more

It has been demonstrated that optical pumping of alkali atoms (rubidium and cesium) results to a highly efficient indirect optical orientation of metastable He (2 3 S 1 ) atoms. However, in an attempt to perform the inverse experiment (i.e. to receive spin-polarization of alkali atoms upon optical pumping of metastable helium atoms) the result was quite unexpected: the magnetic resonance signal of Cs or Rb atoms was very weak (several hundred times weaker compared to conventional optical pumping of helium in the presence of cesium (rubidium)). We propose an explanation for the unusually small ratio of the magnetic resonance signals from Cs (Rb) and metastable He atoms under condition of optical orientation of He atoms. Except of Cs atoms we are the first to have observed magnetic resonance signals from atoms of 85 Rb and 87 Rb isotopes when using the indirect optical orientation in conditions of helium-rubidium gas discharge plasma. It is shown that the anomaly in the amplitude ratios of the observed MR signals can be explained by the unidirectional action of three different factors (the presence of a large nuclear spin of alkali atoms, depolarization of alkali atoms between collisions, and spin exchange between atoms of rubidium isotopes (for the He-Rb system).

K. T. Hecht

David S. Simon

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.