High-resolution optical magnetic resonance imaging of electronic spin polarization in miniaturized atomic sensors

Abstract

Miniaturized atomic sensors of magnetic field and inertia have great potential to be applied as geophysical instruments and in the detection of biomolecules. The distribution of the electronic spin polarization plays a key role as it defines the amount of noble gas that can achieve a state of hyperpolarization, which in turn determines the technique's accuracy and, consequently, its resolution. However, the current techniques for electronic spin polarization imaging are unsuited for the operating conditions of miniaturized atomic sensors besides only accomplishing submillimeter spatial resolution. In this study, optical magnetic resonance is applied to obtain electronic spin polarization images with a spatial resolution of 60 μm experimentally and 10 μm theoretically. This corresponds to an increase by one order of magnitude in resolution when compared to previous reports of electronic spin polarization imaging. By sweeping the RF frequency of the magnetic field while applying a magnetic field gradient of 0.22 [Formula: see text], it is possible to measure electronic spin polarization images for different average photon spins and pump beam positions. Spin polarization images present a high degree of correlation with pump beam images. Furthermore, this image method can be applied to suppressing the inhomogeneities in miniaturized cells, leading to a gain in signal-to-noise ratio. It also offers an opportunity to experimentally perform two-dimensional atomic polarization manipulation in the gas phase, optically transparent solids, and liquids.

A Miniaturized Spin‐Exchange Relaxation‐Free Atomic Magnetometer Array Based on a 1 × 8 Planar Lightwave Circuit Waveguide Splitter

“…Alkalimetal magnetometers exploit the energy structure of the ground and excited states to polarize the atoms, employing the coherent precession of polarized atomic spins for magnetic field measurement. [22,23] The SERF atomic magnetometer operates in an environment abundant with alkali metal atoms and a weak magnetic field, leading to a spin-exchange rate between alkali metal atoms that is significantly faster than the Larmour process. The classical Bloch equation can be employed to elucidate the atomic spin process in this ] context.…”

The Xe isotope nuclear resonance frequency shift of NMR angular velocity sensors due to transverse gradient magnetic fields

“…Atomic sensors based on the spin-exchange optical pumping of noble gases have been developed in many instruments because of their low intrinsic noise, miniaturization, and low power consumption, such as spin-exchange relaxation-free atomic magnetometers [1,2], nuclear magnetic resonance (NMR) angular velocity sensors [3,4], atomic clocks [5,6] and many fundamental physics experiments [7,8]. The NMR * Author to whom any correspondence should be addressed.…”

“…In practice, the gradient magnetic field is generally mixed with high-order components, either due to the inner system field or to impurities in the surrounding environment. Sheng et al [15] studied the precession frequency shift of 3 He and 129 Xe caused by the second-order gradient magnetic field and discovered that it is proportional to the third power of the gradient magnetic field strength, which cannot be explained by second-order perturbation theory approaches in a 3 He-129 Xe co-magnetometer probed by Rb atoms. And they developed an approach for calculating the spin relaxation and frequency shifts based on the Torrey equation and confirmed it experimentally.…”