This paper demonstrates the concept of an optical magnetometer for magnetocardiography. The magnetometer employs a standard Least-Mean-Squares (LMS) algorithm for heart magnetic field measurement within unshielded environment. Experimental results show that the algorithm can extract a weak heart signal from a much-stronger magnetic noise and detect the P, QRS, and T heart features and completel...

An all-optical atomic magnetometer is used to detect a proton free-precession signal from a water sample polarized in a 0.7 T field and remotely analyzed in a 4 microT field. Nuclear spins are manipulated either by pi/2 pulses or by non-adiabatic rotation. The magnetometer operates at room temperature, in an unshielded environment and has a dual-channel sensor for differential measurements.

We consider the limitations due to noise (e.g., quantum projection noise and photon shot-noise) on the sensitivity of an idealized atomic magnetometer that utilizes spin squeezing induced by a continuous quantum nondemolition measurement. Such a magnetometer measures spin precession of N atomic spins by detecting optical rotation of far-detuned light. We show that for very short measurement tim...

We examined the efficiency of the flux-gate magnetometers, MB-160 and MB-162, Shimadzu, which we use for variation observation at the Kakioka Magnetic Observatory. We also examined our method and the equipment for the calibration of the installed calibration apparatus in the flux-gate magnetometer. On the basis of examinations, we obtained the following conclusions: 1. Using our equipment for t...

With the demand for fast response of magnetic field measurement and development laser diode technology, self-oscillating laser-pumped atomic magnetometers have become a new trend. In this work, we designed portable VCSEL-pumped Cs atom magnetometer, including probe (optical path) circuits. The signal amplification feedback loop VCSEL control unit, cell temperature unit were realized. We tested ...

The standard observatory procedure for determining a geomagnetic field’s declination and inclination absolutely is the DI-flux measurement. The instrument consists of a non-magnetic theodolite equipped with a single-axis fluxgate magnetometer. Additionally, a scalar magnetometer is needed to provide all three components of the field. Using only 12 measurement steps, all systematic errors can be...

The fundamental eigenfrequencies of standing Alfvén waves on closed geomagnetic field lines are estimated for the region spanning 5.9 ≤ L < 9.5 over all MLT (Magnetic Local Time). The T96 magnetic field model and a realistic empirical plasma mass density model are employed using the time-of-flight approximation, refining previous calculations that assumed a relatively simplistic mass density mo...

We report transport measurements as a function of bias in open semiconductor quantum dots. These measurements are well described by an effective electron temperature derived from Joule heating at the point contacts and cooling by Wiedemann-Franz out-diffusion of thermal electrons. Using this model, we propose and analyze a quantum dot based sensor which measures absolute magnetic field at micro...