Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE Sensors Letters

The Characterization of Atomic Vapor Cells for High-Sensitivity Magnetic Field Measurements in SERF Regime

Murat Salim Karabinaoğlu, Berfin Muhlise Caklı, Mehmet Hüseyin Sevim

Published Feb 24, 2025• 5 citations
Publisher

Abstract

Nowadays, quantum sensor research is a very interesting and popular topic. High-sensitivity magnetic field measurements using quantum sensors have evolved into the most sensitive magnetic field sensor category today with the invention of atomic magnetometers operating in the spin-exchange relaxation-free (SERF) regime. This letter was prepared to investigate the magnetic field sensitivity changes depending on the buffer gas, temperature, and laser intensity using indigenously produced atomic vapor cells. In addition, the aim was to determine the optimum operating conditions of the atomic magnetometer operating in the SERF regime. As a result, the resonance linewidth and signal-to-noise ratio were measured, and the minimum detectable magnetic field was calculated. According to the obtained results, the lowest magnetic field for Cells I–III was measured as 5.12, 4.21, and 4.81 pT, respectively. The lowest magnetic field of all conditions was obtained in vapor cell (Cell-II) at 100 °C with 5 mW laser intensity. As a result, it has been experimentally proven that under the same conditions, increasing the buffer gas pressure in vapor cells can narrow the resonance linewidth, and the magnetic field sensitivity can be improved by increasing the laser intensity applied to the vapor cells.

DOI
10.1109/lsens.2025.3544963

Related papers

Influence of Buffer-Gas Pressure Inside Micro Alkali Vapor Cells on the Performance of Chip-Scale SERF Magnetometers

Lei Wu, Jintang Shang, Yu Ji +2 more

Spin-exchange-relaxation-free (SERF) optical atomic magnetometers are facing the challenges of dramatic decrease of sensitivity when the alkali vapor cells become small. This paper focuses on the sensitivity improvement of the chip-scale atomic magnetometer (CSAM) by changing buffer-gas pressures inside the microfabricated vapor cells. The rubidium vapor cells with three different buffer-gas pressures were tested in the SERF magnetometer. The influences of vapor cell temperature and pumping laser power on the device sensitivity are also characterized for further optimization. Results show that the three atomic vapor cells, with N2buffer-gas pressure of 0.20, 0.88, and 2.35 amg, have sensitivities of 900, 500, and 150 fT/Hz1/2, respectively. Results indicated that when the alkali vapor cells continue to be smaller, high buffer-gas pressure would provide an effective way to reduce the wall collision and improve the performance of CSAMs.

IEEE Transactions on Components Packaging and Manufacturing Technology•Dec 21, 2017•18 citations

Ultrasensitive SERF atomic magnetometer with a miniaturized hybrid vapor cell

Yintao Ma, Yao Chen, Mingzhi Yu +8 more

Abstract The chip-scale hybrid optical pumping spin-exchange relaxation-free (SERF) atomic magnetometer with a single-beam arrangement has prominent applications in biomagnetic measurements because of its outstanding features, including ultrahigh sensitivity, an enhanced signal-to-noise ratio, homogeneous spin polarization and a much simpler optical configuration than other devices. In this work, a miniaturized single-beam hybrid optical pumping SERF atomic magnetometer based on a microfabricated atomic vapor cell is demonstrated. Although the optically thin Cs atoms are spin-polarized, the dense Rb atoms determine the experimental results. The enhanced signal strength and narrowed resonance linewidth are experimentally proven, which shows the superiority of the proposed magnetometer scheme. By using a differential detection scheme, we effectively suppress optical noise with an approximate five-fold improvement. Moreover, the cell temperature markedly affects the performance of the magnetometer. We systematically investigate the effects of temperature on the magnetometer parameters. The theoretical basis for these effects is explained in detail. The developed miniaturized magnetometer has an optimal magnetic sensitivity of 20 fT/Hz 1/2 . The presented work provides a foundation for the chip-scale integration of ultrahighly sensitive quantum magnetometers that can be used for forward-looking magnetocardiography (MCG) and magnetoencephalography (MEG) applications.

Microsystems & Nanoengineering•Aug 30, 2024•62 citations

Spin-exchange-relaxation-free magnetometry with Cs vapor

M. P. Ledbetter, Igor Savukov, Víctor M. Acosta +2 more

We describe a Cs atomic magnetometer operating in the spin-exchange-relaxation-free (SERF) regime. With a vapor cell temperature of $103\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ we achieve intrinsic magnetic resonance widths $\ensuremath{\Delta}B=17\text{ }\ensuremath{\mu}\text{G}$ corresponding to an electron spin-relaxation rate of $300\text{ }{\text{s}}^{\ensuremath{-}1}$ when the spin-exchange rate is ${\ensuremath{\Gamma}}_{\text{SE}}=14\text{ }000\text{ }{\text{s}}^{\ensuremath{-}1}$. We also observe an interesting narrowing effect due to diffusion. Signal-to-noise measurements yield a sensitivity of about $400\text{ }\text{pG}/\sqrt{\text{Hz}}$. Based on photon shot noise, we project a sensitivity of $40\text{ }\text{pG}/\sqrt{\text{Hz}}$. A theoretical optimization of the magnetometer indicates sensitivities on the order of $2\text{ }\text{pG}/\sqrt{\text{Hz}}$ should be achievable in a $1\text{ }{\text{cm}}^{3}$ volume. Because Cs has a higher saturated vapor pressure than other alkali metals, SERF magnetometers using Cs atoms are particularly attractive in applications requiring lower temperatures.

arXiv:0708.1012•Physical Review A•Mar 13, 2008•400 citations

Study of resonance curve width in Cs vapor magnetometer

Sun Weimin

A new magnetometer with Cs vapor in the spin exchange relaxation free(SERF) regime is described.Cs has a higher saturated vapor pressure than other alkali metals;so cesium SERF magnetometer is particularly attractive in applications that require lower power dissipation.Four factors affect atomic transverse relaxations in the SERF magnetometer,including collisions and diffusions among Cs,N2 and He,laser pumping and detecting processes;the buffer gas pressure of He that affects the relaxation is calculated and discussed emphatically in theory at 105 ℃,the result shows that the optimum buffer gas pressure is 350×133.3 Pa.Under the optimum pressure,the polarized spectrum linewidth as the function of the cell temperature is discussed briefly.It is found the least linewidth is only 3.7 Hz corresponding to the electric spin relaxation rate of 278 s-1 at 105 ℃.The result provides a help to increase the sensitivity of the magnetometer with Cs vapor.

Journal of Optoelectronics·laser•Jan 1, 2010•0 citations

Buffer Gas Pressure Optimization for Atomic Spin Relaxation Suppression in Ultra-High-Sensitivity SERF Magnetometers

Siran Li, X.-G. Lu, Yinghui Zhang +3 more

Optically pumped magnetometers (OPM) are core quantum payloads for geomagnetic remote sensing. Among them, the spin-exchange relaxation-free (SERF) OPM with aT-level ultimate sensitivity stands as mainstream. While enlarging the alkali-metal vapor cell of the SERF OPM enhances sensitivity, it triggers complex atomic spin relaxation, notably intensified magnetic field gradient relaxation. To address the dilemma of atomic spin relaxation regulation and the engineering requirements of ultra-high-sensitivity SERF magnetometers, this paper constructs an analytical model of the total relaxation rate that comprehensively considers wall-collision relaxation, spin-destruction collision relaxation, and longitudinal/transverse magnetic field gradient relaxation, etc. The analytical relationship between buffer gas pressure and total relaxation rate for a commonly used spherical vapor cell is derived, revealing the intrinsic correlation among cell size, atomic spin relaxation, and optimal pressure. Based on the theoretical model, the filling parameters of the vapor cell are optimized, and experimental measurements are carried out. The theoretical relaxation results are highly consistent with the experimental ones, realizing the precise optimization of buffer gas pressure. The optimization method proposed in this paper provides a theoretical basis and parameter guidance for the engineering preparation of alkali-metal vapor cells for high-sensitivity SERF magnetometers in remote sensing applications.

Photonics•Jun 1, 2026•0 citations

Femtotesla Spin-Exchange Relaxation-Free Atomic Magnetometer With a Multipass Cell

Yibo Qi, Bo Li, Shuying Wang +3 more

Miniaturized high-sensitivity atomic magnetometers play a crucial role in biomagnetic measurements. The utilization of multipass cells enhances the sensitivity of atomic magnetometers. This study explores the benefits of employing a multipass cell in spin-exchange relaxation-free (SERF) atomic magnetometers through theoretical and experimental analysis. A signal-to-noise ratio (SNR) model was established by accounting for the optimal detuning frequency of the probe light and low-frequency 1/f noise. This enabled the optimal number of probe light passes through the vapor cell to be determined. Additionally, compact and symmetric reflective optical paths were designed to mitigate polarization gradients in atomic magnetometers with high atomic number density. Experimental results confirmed that the magnetic field sensitivity of the triple-pass configuration (1.8 fT/Hz$^{1/2}$) was 1.89 times that of the single-pass configuration (3.4 fT/Hz$^{1/2}$), consistent with the theoretical analysis. This study provides valuable theoretical guidance for analyzing the SNR performance of SERF atomic magnetometers and demonstrates the potential of multipass cells in enhancing their magnetic field sensitivity. The utilization of multipass cells presents a viable approach toward the realization of highly sensitive and portable miniaturized SERF atomic magnetometers.

IEEE Transactions on Instrumentation and Measurement•Jan 1, 2024•18 citations
Nowadays, quantum sensor research is a very interesting and popular topic. High-sensitivity magnetic field measurements using quantum sensors have evolved into the most sensitive magnetic field sensor category today with the invention of atomic magnetometers operating in the spin-exchange relaxation-free (SERF) regime. This letter was prepared to investigate the magnetic field sensitivity changes depending on the buffer gas, temperature, and laser intensity using indigenously produced atomic vapor cells. In addition, the aim was to determine the optimum operating conditions of the atomic magnetometer operating in the SERF regime. As a result, the resonance linewidth and signal-to-noise ratio were measured, and the minimum detectable magnetic field was calculated. According to the obtained results, the lowest magnetic field for Cells I–III was measured as 5.12, 4.21, and 4.81 pT, respectively. The lowest magnetic field of all conditions was obtained in vapor cell (Cell-II) at 100 °C with 5 mW laser intensity. As a result, it has been experimentally proven that under the same conditions, increasing the buffer gas pressure in vapor cells can narrow the resonance linewidth, and the magnetic field sensitivity can be improved by increasing the laser intensity applied to the vapor cells.
Spin-exchange-relaxation-free (SERF) optical atomic magnetometers are facing the challenges of dramatic decrease of sensitivity when the alkali vapor cells become small. This paper focuses on the sensitivity improvement of the chip-scale atomic magnetometer (CSAM) by changing buffer-gas pressures inside the microfabricated vapor cells. The rubidium vapor cells with three different buffer-gas pressures were tested in the SERF magnetometer. The influences of vapor cell temperature and pumping laser power on the device sensitivity are also characterized for further optimization. Results show that the three atomic vapor cells, with N2buffer-gas pressure of 0.20, 0.88, and 2.35 amg, have sensitivities of 900, 500, and 150 fT/Hz1/2, respectively. Results indicated that when the alkali vapor cells continue to be smaller, high buffer-gas pressure would provide an effective way to reduce the wall collision and improve the performance of CSAMs.
Abstract The chip-scale hybrid optical pumping spin-exchange relaxation-free (SERF) atomic magnetometer with a single-beam arrangement has prominent applications in biomagnetic measurements because of its outstanding features, including ultrahigh sensitivity, an enhanced signal-to-noise ratio, homogeneous spin polarization and a much simpler optical configuration than other devices. In this work, a miniaturized single-beam hybrid optical pumping SERF atomic magnetometer based on a microfabricated atomic vapor cell is demonstrated. Although the optically thin Cs atoms are spin-polarized, the dense Rb atoms determine the experimental results. The enhanced signal strength and narrowed resonance linewidth are experimentally proven, which shows the superiority of the proposed magnetometer scheme. By using a differential detection scheme, we effectively suppress optical noise with an approximate five-fold improvement. Moreover, the cell temperature markedly affects the performance of the magnetometer. We systematically investigate the effects of temperature on the magnetometer parameters. The theoretical basis for these effects is explained in detail. The developed miniaturized magnetometer has an optimal magnetic sensitivity of 20 fT/Hz 1/2 . The presented work provides a foundation for the chip-scale integration of ultrahighly sensitive quantum magnetometers that can be used for forward-looking magnetocardiography (MCG) and magnetoencephalography (MEG) applications.
We describe a Cs atomic magnetometer operating in the spin-exchange-relaxation-free (SERF) regime. With a vapor cell temperature of $103\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ we achieve intrinsic magnetic resonance widths $\ensuremath{\Delta}B=17\text{ }\ensuremath{\mu}\text{G}$ corresponding to an electron spin-relaxation rate of $300\text{ }{\text{s}}^{\ensuremath{-}1}$ when the spin-exchange rate is ${\ensuremath{\Gamma}}_{\text{SE}}=14\text{ }000\text{ }{\text{s}}^{\ensuremath{-}1}$. We also observe an interesting narrowing effect due to diffusion. Signal-to-noise measurements yield a sensitivity of about 400 pG/Hz400\text{ }\text{pG}/\sqrt{\text{Hz}}400 pG/Hz​. Based on photon shot noise, we project a sensitivity of 40 pG/Hz40\text{ }\text{pG}/\sqrt{\text{Hz}}40 pG/Hz​. A theoretical optimization of the magnetometer indicates sensitivities on the order of 2 pG/Hz2\text{ }\text{pG}/\sqrt{\text{Hz}}2 pG/Hz​ should be achievable in a 1 cm31\text{ }{\text{cm}}^{3}1 cm3 volume. Because Cs has a higher saturated vapor pressure than other alkali metals, SERF magnetometers using Cs atoms are particularly attractive in applications requiring lower temperatures.
A new magnetometer with Cs vapor in the spin exchange relaxation free(SERF) regime is described.Cs has a higher saturated vapor pressure than other alkali metals;so cesium SERF magnetometer is particularly attractive in applications that require lower power dissipation.Four factors affect atomic transverse relaxations in the SERF magnetometer,including collisions and diffusions among Cs,N2 and He,laser pumping and detecting processes;the buffer gas pressure of He that affects the relaxation is calculated and discussed emphatically in theory at 105 ℃,the result shows that the optimum buffer gas pressure is 350×133.3 Pa.Under the optimum pressure,the polarized spectrum linewidth as the function of the cell temperature is discussed briefly.It is found the least linewidth is only 3.7 Hz corresponding to the electric spin relaxation rate of 278 s-1 at 105 ℃.The result provides a help to increase the sensitivity of the magnetometer with Cs vapor.
Optically pumped magnetometers (OPM) are core quantum payloads for geomagnetic remote sensing. Among them, the spin-exchange relaxation-free (SERF) OPM with aT-level ultimate sensitivity stands as mainstream. While enlarging the alkali-metal vapor cell of the SERF OPM enhances sensitivity, it triggers complex atomic spin relaxation, notably intensified magnetic field gradient relaxation. To address the dilemma of atomic spin relaxation regulation and the engineering requirements of ultra-high-sensitivity SERF magnetometers, this paper constructs an analytical model of the total relaxation rate that comprehensively considers wall-collision relaxation, spin-destruction collision relaxation, and longitudinal/transverse magnetic field gradient relaxation, etc. The analytical relationship between buffer gas pressure and total relaxation rate for a commonly used spherical vapor cell is derived, revealing the intrinsic correlation among cell size, atomic spin relaxation, and optimal pressure. Based on the theoretical model, the filling parameters of the vapor cell are optimized, and experimental measurements are carried out. The theoretical relaxation results are highly consistent with the experimental ones, realizing the precise optimization of buffer gas pressure. The optimization method proposed in this paper provides a theoretical basis and parameter guidance for the engineering preparation of alkali-metal vapor cells for high-sensitivity SERF magnetometers in remote sensing applications.
Miniaturized high-sensitivity atomic magnetometers play a crucial role in biomagnetic measurements. The utilization of multipass cells enhances the sensitivity of atomic magnetometers. This study explores the benefits of employing a multipass cell in spin-exchange relaxation-free (SERF) atomic magnetometers through theoretical and experimental analysis. A signal-to-noise ratio (SNR) model was established by accounting for the optimal detuning frequency of the probe light and low-frequency 1/f noise. This enabled the optimal number of probe light passes through the vapor cell to be determined. Additionally, compact and symmetric reflective optical paths were designed to mitigate polarization gradients in atomic magnetometers with high atomic number density. Experimental results confirmed that the magnetic field sensitivity of the triple-pass configuration (1.8 fT/Hz1/2^{1/2}1/2) was 1.89 times that of the single-pass configuration (3.4 fT/Hz1/2^{1/2}1/2), consistent with the theoretical analysis. This study provides valuable theoretical guidance for analyzing the SNR performance of SERF atomic magnetometers and demonstrates the potential of multipass cells in enhancing their magnetic field sensitivity. The utilization of multipass cells presents a viable approach toward the realization of highly sensitive and portable miniaturized SERF atomic magnetometers.