We first report a single-light-source orthogonally pumped triaxial atomic magnetometer with a double-cell structure. By using a beam splitter to equally allocate the pump beam, the proposed triaxial atomic magnetometer is responsive to magnetic fields in all three directions, and without sacrificing system sensitivity. The experimental results indicate that, the magnetometer achieves a sensitivity of 22 fT/Hz 1/2 in x-direction with a 3-dB bandwidth of 22 Hz, a sensitivity of 23 fT/Hz 1/2 in y-direction with a 3-dB bandwidth of 23 Hz, and a sensitivity of 21 fT/Hz 1/2 in z-direction with a 3-dB bandwidth of 25 Hz. This magnetometer is useful for the applications that require the measurements of the three components of the magnetic field.
We first report a single-light-source orthogonally pumped triaxial atomic magnetometer with a double-cell structure. By using a beam splitter to equally allocate the pump beam, the proposed triaxial atomic magnetometer is responsive to magnetic fields in all three directions, and without sacrificing system sensitivity. The experimental results indicate that, the magnetometer achieves a sensitivity of 22 fT/Hz 1/2 in x-direction with a 3-dB bandwidth of 22 Hz, a sensitivity of 23 fT/Hz 1/2 in y-direction with a 3-dB bandwidth of 23 Hz, and a sensitivity of 21 fT/Hz 1/2 in z-direction with a 3-dB bandwidth of 25 Hz. This magnetometer is useful for the applications that require the measurements of the three components of the magnetic field.
The SERF atomic magnetometer is nowadays the most sensitive equipment for magnetic field measurement. As used in triaxial magnetic field measurements, however, the weak interaction of the polarized atoms with the magnetic field in the pump light direction results in low sensitivity in that direction. To solve this issue, a single-beam orthogonal pumping triaxial atomic magnetometer based on a double-cell structure is demonstrated. In this paper, we use a beam-splitter to split the pumping light beam equally, so that the proposed triaxial atomic magnetometer can respond to magnetic fields in all three axes simultaneously, and with no sacrifice in sensitivity. The experiments have shown that the magnetometer has a sensitivity of 46fT/Hz1/2on the x-axis, 32fT/Hz1/2on the y-axis, and 40fT/Hz1/2on the z-axis. This magnetometer has great potential for applications where the three components of the magnetic field need to be measured.
In this paper, we propose a three-axis atomic magnetometer (AM), in which one light beam is divided into two orthogonal spatially separated pump beams by a lateral displacement polarized beam splitter and reflector mirrors; this scheme suppresses the three-axis crosstalk caused by the interaction between the two beams and atoms in the cell. When the AM operates in the direct-current (DC) mode, the three-axis crosstalk is significant. To solve this problem, three modulation fields with the same amplitudes, frequencies, and different phases are applied, which allow the AM operated in modulation mode to perform a highly sensitive synchronous and independent measurement of the three-axis magnetic field with low crosstalk. The experimental results showed that the three-axis crosstalk was less than 2%. In the modulation mode, the sensitivities were 22, 23, and 26 fT/Hz1/2 on the x-, y-, and z-axes, respectively. The 3-dB bandwidths of the three axes were 126, 124, and 112 Hz. In addition, we demonstrated a three-axis in-situ magnetic compensation method with a magnetic compensation accuracy of the pT level in the DC mode. The proposed triaxial AM can be easily miniaturised and used in biomedical applications, such as in magnetocardiography and magnetoencephalography.
Abstract We display a single-beam triaxial spin-exchange relaxation-free (SERF) atomic magnetometer by utilizing two orthogonal transverse modulation fields perpendicular to the light. The magnetic field’s three-axis vector components can be extracted simultaneously and independently from the transmitted light by lock-in amplifiers with reference to the different demodulated frequencies. We find that the residual magnetic field is a significant factor that could affect triaxial coupling, and specially the influence of the z -axis remanence on xy -axis coupling is studied in detail. Under the optimal parameters, the three-axis sensitivities are 20 fT Hz − 1 / 2 in the x - and y - axis, and 230 fT Hz − 1 / 2 in the z -axis. Meanwhile, the three-axis bandwidths are 110 Hz, 138 Hz and 211 Hz in the x -, y - and z -axis, respectively. The proposed single-beam triaxial SERF atomic magnetometer could be used to construct a compact and low-cost atomic sensor that is particularly suitable for the vector measurement of the biomagnetic such as magnetoencephalography and magnetocardiography.
The high-sensitivity three-axis detection of magnetic fields is widely used in various applications.Our study demonstrates an atomic magnetometer detecting vector magnetic field, of which the core components are one glass cell and two elliptically polarized laser beams.The light-intensity noise is suppressed by differential detection technology, so a higher sensitivity is obtained compared with our previous work.The three-axis average sensitivities of the atomic magnetometer simultaneously reached 14 fT/Hz 1/2 along the x axis, 11 fT/Hz 1/2 along the y axis, and 25 fT/Hz 1/2 along the z axis.Furthermore, the atomic magnetometer's dynamic range was further improved to 150 nT, and its bandwidth was increased to over 200 Hz using a closed-loop control system.The proposed three-axis atomic magnetometer with a large dynamic range and a wide bandwidth holds great promise for biomagnetic measurement in a more challenging environment.
Three-axis atomic magnetometers have great advantages for interpreting information conveyed by magnetic fields. Here, we demonstrate a compact construction of a three-axis vector atomic magnetometer. The magnetometer is operated with a single laser beam and with a specially designed triangular 87Rb vapor cell (side length is 5 mm). The ability of three-axis measurement is realized by reflecting the light beam in the cell chamber under high pressure, so that the atoms before and after reflection are polarized along two different directions. It achieves a sensitivity of 40 fT/Hz in x-axis, 20 fT/Hz in y-axis, and 30 fT/Hz in z-axis under spin-exchange relaxation-free regime. The crosstalk effect between different axes is proven to be little in this configuration. The sensor configuration here is expected to form further values, especially for vector biomagnetism measurement, clinical diagnosis, and field source reconstruction.
We propose a three-axis closed-loop optically pumped magnetometer with high sensitivity. The closed-loop magnetometer has a three-axis sensitivity of approximately 30 fT/Hz 1/2 using two orthogonal laser beams for pumping and probing the alkali metal atoms. In the closed-loop mode, the dynamic range is improved from ±5 nT to ±150 nT. The bandwidth is increased from about 100 Hz to over 2 kHz with 10 kHz modulation fields in x - and y -axes and another 6 kHz modulation field along the z -axis. Compared with single-axis or dual-axis magnetometers, the proposed magnetometer not only provides the direction and magnitude of the magnetic field but also has high robustness in a challenging environment. The magnetometer has applications in biomagnetic measurements, magnetic resonance imaging, and fundamental physics.