The Global Network of Optical Magnetometers for Exotic physics searches (GNOME) conducts an experimental search for certain forms of dark matter based on their spatiotemporal signatures imprinted on ...a global array of synchronized atomic magnetometers. The experiment described here looks for a gradient coupling of axion-like particles (ALPs) with proton spins as a signature of locally dense dark matter objects such as domain walls. In this work, stochastic optimization with machine learning is proposed for use in a search for ALP domain walls based on GNOME data. The validity and reliability of this method were verified using binary classification. The projected sensitivity of this new analysis method for ALP domain-wall crossing events is presented.
•A high-sensitivity radio-optical cesium magnetometer is designed and implemented.•Dependencies of the magnetometer performance on some related parameters are studied.•Optimal ranges of these related ...parameters are obtained.
A high-sensitivity radio-optical cesium magnetometer is designed and implemented. By studying the dependencies of the performance of the radio-optical cesium magnetometer on some related parameters, the optimal ranges of these parameters are obtained, and the magnetometer performance is optimized and tested. The test results show that the designed radio-optical cesium magnetometer can achieve a magnetometer sensitivity of 82.5 fT/√Hz, a resolution within 1 pT to an external magnetic field change, and a noise fluctuation of 0.2 pT for an integration time of 1 s.
Abstract
Magnetic encephalography is currently the most informative method of functional study of the brain, since, unlike other methods, it allows one to localise deep sources of biosignals and ...perform three-dimensional mapping of neuronal activity. The main factors hindering the development and spread of this method are the complexity and high cost of diagnostic tools, as well as the rigidity of the requirements they impose on the spatial and temporal uniformity of the magnetic field. The prospects for desinging a device capable of largely overcoming these limitations are considered. A review of studies aimed at developing an optical sensor applicable to magnetic encephalography is presented. The all-optical single-beam nonzero-field sensor proposed by the authors earlier is separately considered.
A miniature atomic scalar magnetometer based on the rubidium isotope 87Rb was developed for operation in space. The instrument design implements both Mx and Mz mode operation and leverages a novel ...microelectromechanical system (MEMS) fabricated vapor cell and a custom silicon‐on‐sapphire (SOS) complementary metal‐oxide‐semiconductor (CMOS) integrated circuit. The vapor cell has a volume of only 1 mm3 so that it can be efficiently heated to its operating temperature by a specially designed, low‐magnetic‐field‐generating resistive heater implemented in multiple metal layers of the transparent sapphire substrate of the SOS‐CMOS chips. The SOS‐CMOS chip also hosts the Helmholtz coil and associated circuitry to stimulate the magnetically sensitive atomic resonance and temperature sensors. The prototype instrument has a total mass of fewer than 500 g and uses less than 1 W of power, while maintaining a sensitivity of 15 pT/√Hz at 1 Hz, comparable to present state‐of‐the‐art absolute magnetometers.
Key Points
Atomic magnetometer for space has a total mass of less than 500 g and uses less than 1 W of power
Miniaturization enabled by MEMS fabrication techniques and low‐power semiconductor lasers
Sensitivity of 15 pT/√Hz at 1 Hz is comparable to present state‐of‐the‐art atomic magnetometers
High precision mapping of weak magnetic fields is of interest for several branches of pure and applied research. This paper presents a resume of the progress made at Fribourg in adapting laboratory ...style laser-pumped optical Cs magnetometers to multisensor field mapping problems. Progress has been made in sensor head design and manufacture, laser beam splitting and control, and signal treatment electronics. A summary of the technology and its applications are presented.
It is shown experimentally that use of fluorescence and transmission spectra obtained from nanocells with the thickness of column of rubidium atomic vapor
L
= λ/2 and
L
= λ, respectively (λ = 794 nm ...is the wavelength of laser radiation close to resonance with
D
1
-line transition of Rb atoms), by means of a narrowband diode laser allows spectral separation and study of variations of probabilities of atomic transitions between ground and excited states of hfs of
D
1
lines of
85
Rb and
87
Rb atoms in the range of magnetic fields from 10 to 5000 G. Small thickness of atomic vapor column (∼390 nm and ∼794 nm) allows applying permanent magnets simplifying essentially creation of strong magnetic fields. Advantages of this technique are discussed as compared with the technique of saturated absorption. The obtained results show that a nanocell with submicrom thickness of vapor column may serve as a basis for designing a magnetometer with submicron local spatial resolution which is important in case of measuring strongly inhomogeneous magnetic fields. Experimental data are in good agreement with the theoretical results.
We present a scheme for an all-optical self-oscillating magnetometer based on the opto-electronic oscillator stabilized with an atomic vapor cell. We demonstrate a proof of the principle with DC ...magnetic field measurements characterized by 2×10−7 G sensitivity and 1–1000 mG dynamic range.
We describe a portable four-channel array of chip-scale atomic magnetometers in a flexible flying-lead configuration. These microfabricated, uncooled sensors with volumes below 1 cm3 demonstrate ...sensitivities around 100 fT/Hz1/2 and bandwidths of several hundred hertz. Performance limits are discussed, as the design is easily scalable to different sensor sizes and large arrays. Initial measurements of MCG are crossvalidated with SQUID measurements.
Diamond-based optical vector magnetometer Segura, Charlie Oncebay; Muniz, Sergio Ricardo
2021 SBFoton International Optics and Photonics Conference (SBFoton IOPC),
2021-May-31
Conference Proceeding
Odprti dostop
We describe the construction and characterization of a high-resolution optical magnetometer to measure the full vector magnetic field on an ultrathin layer near the surface of the device. This ...solid-state device is based on quantum sensors created by a layer of nitrogen-vacancy (NV) centers less than 20 nm below the surface of an ultrapure diamond. This ensemble of nanosensors provides a versatile device capable of mapping magnetic fields and surface current densities with a sub-micrometer resolution and high sensitivity, making it suitable for many applications. Here, we show a custom-built prototype to demonstrate an operating proof-of-concept device.
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