Spin image of an atomic vapor cell with a resolution smaller than the diffusion crosstalk free distance

Abstract

The diffusion crosstalk free distance is an important parameter for spin images in atomic vapor cells and is also regarded as a limit on the spatial resolution. However, by modulating the pumping light both spatially and temporally using a digital micromirror device, a spin image of a vapor cell has been obtained with a distinguishable stripe width of 13.7 µm, which is much smaller than the corresponding diffusion crosstalk free distance of ∼138 µm. The fundamental limit on the spatial resolution as determined by diffusion and the uncertainty principle is analyzed.

Free-induction-decay magnetic field imaging with a microfabricated Cs vapor cell

“…One can consider a buffer gas vapor cell as an array of locally independent sensors whose size is equivalent to the distance travelled by the atoms during a measurement. This is known as the diffusion crosstalk-free distance which can be estimated as, ∆x = √ 2DT , where D is the diffusion constant calculated for Cs atoms in a N 2 atmosphere of a specific pressure and temperature, and T is the measurement time [35,36]. This yields close to 300 µm when taking into account the 220 torr buffer gas pressure of the cell and the readout period of a single FID cycle.…”

Recent Developments in Fabrication Methods and Measurement Schemes for Optically Pumped Magnetic Gradiometers: A Comprehensive Review

“…In these applications, gradiometer measurements with baselines ranging from millimeters to centimeters are commonly employed to minimize background common-mode fields. The second motivation puts more attention on the magnetic field image and/or spin polarization image itself, where spatial resolution can be down to microns or even nanometers [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. In this review, we focus on the first case, i.e., a gradiometer based on an optically pumped vapor cell.…”