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Spectrogram of the 8Hz – 12Hz alpha-band response to a participant opening/closing their eyes (a) and a schematic of the participant lying in the shield with the back of their head pushed up against the modular OPM system (b). The overlaid white trace denotes the audio cue trigger signal from the stimulus PC. High values of the trigger signal indicate the time when the participant is instructed to close their eyes, and the low value is when the participant has their eyes open. The spectrogram colour scheme details the high periods of activity in yellow, and the low periods in green. A peak in activity of 1pT/Hz is observed in the 8Hz – 12Hz region during the third eyes-closed time period.
Source publication
To address the demands in healthcare and industrial settings for spatially resolved magnetic imaging, we present a modular optically pumped magnetometer (OPM) system comprising a multi-sensor array of highly sensitive quantum magnetometers. This system is designed and built to facilitate fast prototyping and testing of new measurement schemes by en...
Citations
... Some of these systems utilize BECs [30,31,41] or cold atoms [42,43] to achieve excellent spatial resolution and sensitivity. Vapor cells enable diverse applications including absorption imaging with vortex laser beams for 3D vector B-field measurements [29], vapor cell gradiometers [44][45][46][47], and arrays [48][49][50]. ...
An inter-combination transition in Yb enables a novel approach for rapidly imaging magnetic field variations with excellent spatial and temporal resolution and accuracy. This quantum imaging magnetometer reveals "dark stripes" that are contours of constant magnetic field visible by eye or capturable by standard cameras. These dark lines result from a combination of Autler-Townes splitting and the spatial Hanle effect in the transition of Yb when driven by multiple strong coherent laser fields (carrier and AM/FM modulation sidebands of a single-mode 556 nm laser). We show good agreement between experimental data and our theoretical model for the closed, 4-level Zeeman shifted V-system and demonstrate scalar and vector magnetic fields measurements at video frame rates over spatial dimensions of 5 cm (expandable to 1 m) with 0.1 mm resolution. Additionally, the transition allows for s response time and a large dynamic range (T to many Ts).
... As an alternative approach to combining a growing number of commercial or research-level individual OPM sensors into arrays, scalable high-density OPMs in miniaturized and integrated assemblies could be used as magnetic imaging chips or cameras [131]. This type of approach addresses multiple challenges present in current systems: (1) A higher sensing density of <10 mm sensorsensor spacing enables more accurate source localization. ...
Magnetoencephalography (MEG) allows the non-invasive measurement of brain activity at millisecond precision combined with localization of the underlying generators. So far, MEG-systems consisted of superconducting quantum interference devices (SQUIDS), which suffer from several limitations. Recent technological advances, however, have enabled the development of novel MEG-systems based on optically pumped magnetometers (OPMs), offering several advantages over conventional SQUID-MEG systems. Considering potential improvements in the measurement of neuronal signals as well as reduced operating costs, the application of OPM-MEG systems for clinical neuroscience and diagnostic settings is highly promising. Here we provide an overview of the current state-of-the art of OPM-MEG and its unique potential for translational neuroscience. First, we discuss the technological features of OPMs and benchmark OPM-MEG against SQUID-MEG and electroencephalography (EEG), followed by a summary of pioneering studies of OPMs in healthy populations. Key applications of OPM-MEG for the investigation of psychiatric and neurological conditions are then reviewed. Specifically, we suggest novel applications of OPM-MEG for the identification of biomarkers and circuit deficits in schizophrenia, dementias, movement disorders, epilepsy, and neurodevelopmental syndromes (autism spectrum disorder and attention deficit hyperactivity disorder). Finally, we give an outlook of OPM-MEG for translational neuroscience with a focus on remaining methodological and technical challenges.
