High spatial resolution multi-channel optically pumped atomic magnetometer based on a spatial light modulator

Abstract

Ultra-sensitive multi-channel optically pumped atomic magnetometers based on the spin-exchange relaxation-free (SERF) effect are powerful tools for applications in the field of magnetic imaging. To simultaneously achieve ultra-high spatial resolution and ultra-high magnetic field sensitivity, we proposed a high-resolution multi-channel SERF atomic magnetometer for two-dimensional magnetic field measurements based on a digital micro-mirror device (DMD) as the spatial light modulator for a single vapor cell. Under the optimal experimental conditions obtained via spatial and temporal modulation of the probe light, we first demonstrated that the average sensitivity of the proposed 25-channel magnetometer was approximately 25fT/Hz1/2 with a spatial resolution of 216µm. Then, we measured the magnetic field distribution generated by a gradient coil and compared the experimentally obtained distributions with those calculated via finite element simulation. The obtained g value of 99.2% indicated good agreement between our experimental results and the theoretical calculations, thereby confirming that our proposed multi-channel SERF magnetometer was effective at measuring magnetic field distributions with an ultra-high spatial resolution.

Analysis and Measurement of Differential-Mode Magnetic Noise in Mn-Zn Soft Ferrite Shield for Ultra-Sensitive Sensors

“…The loss caused by the current generated by the hypothetical excitation loop is indirectly calculated by the complex permeability and conductivity of the magnetic shielding material. For metal materials, such as silicon steel sheet and mu-metal, the conductivity is high and the eddy current noise is large ( σ ~ 10 6 Ω −1 m −1 ), resulting in a large magnetic noise, about ~10 fT/Hz 1/2 [ 11 ]. For the ferrite materials, the conductivity is very weak ( σ ~ 10 Ω −1 m −1 ), so the eddy current loss is very small and hysteresis loss is dominant.…”

“…Mu-metal materials with high permeability (>30,000) are widely used in passive magnetic shields [ 9 , 10 , 11 ]. However, the high electrically conducting mu-metal materials also generated high intrinsic magnetic noise owing to Johnson current, which becomes the main factor limiting the sensitivity of many atomic sensors, especially ultra-high sensitive atomic magnetometers [ 12 , 13 , 14 ].…”

Atomic Magnetometer Achieves Visual Salience Analysis in Drosophila

“…The circular component of the light creates relatively uniform spin polarization, and the linear component is used to measure optical rotation generated by the atoms. The following is the Bloch equation describing the polarization state of atoms in the cell [ 24 , 25 , 26 , 27 , 28 ]: where is an atomic polarization state. is the slowing-down factor.…”

Surface-Wave Propagation on Non-Hermitian Metasurfaces with Extreme Anisotropy

“…Similar considerations hold for the inductive case too. As for the practical realizability of the required gain-loss spatial modulation, one possibility could be to rely on highresolution selective optical pumping [65], possibly based on digital spatial light modulators [66]. Alternatively, one could think of relying on a uniform optical pumping, and patterning a thin layer of gain material with thin, lossy strips, so as to suitably overcompensate the gain in certain selected regions.…”