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

Scientific Reports

Elliptical polarization of near-resonant linearly polarized probe light in optically pumped alkali metal vapor

Yingying Li, Zhiguo Wang, Shilong Jin, Jie Yuan, Hui Luo

Published Feb 20, 2017• 9 citations
Publisher

Abstract

Optically pumped alkali metal atoms currently provide a sensitive solution for magnetic microscopic measurements. As the most practicable plan, Faraday rotation of linearly polarized light is extensively used in spin polarization measurements of alkali metal atoms. In some cases, near-resonant Faraday rotation is applied to improve the sensitivity. However, the near-resonant linearly polarized probe light is elliptically polarized after passing through optically pumped alkali metal vapor. The ellipticity of transmitted near-resonant probe light is numerically calculated and experimentally measured. In addition, we also analyze the negative impact of elliptical polarization on Faraday rotation measurements. From our theoretical estimate and experimental results, the elliptical polarization forms an inevitable error in spin polarization measurements.

DOI
10.1038/srep43066

Related papers

Sensitive determination of the spin polarization of optically pumped alkali-metal atoms using near-resonant light

Zhichao Ding, Xingwu Long, Jie Yuan +2 more

A new method to measure the spin polarization of optically pumped alkali-metal atoms is demonstrated. Unlike the conventional method using far-detuned probe light, the near-resonant light with two specific frequencies was chosen. Because the Faraday rotation angle of this approach can be two orders of magnitude greater than that with the conventional method, this approach is more sensitive to the spin polarization. Based on the results of the experimental scheme, the spin polarization measurements are found to be in good agreement with the theoretical predictions, thereby demonstrating the feasibility of this approach.

Scientific Reports•Sep 6, 2016•26 citations

Spin-exchange relaxation-free magnetometry using elliptically polarized light

Vishal Shah, Michael V. Romalis

Spin-exchange relaxation free alkali-metal magnetometers typically operate in the regime of high optical density, presenting challenges for simple and efficient optical pumping and detection. We describe a high-sensitivity Rb magnetometer using a single elliptically polarized off-resonant laser beam. Circular component of the light creates relatively uniform spin polarization while the linear component is used to measure optical rotation generated by the atoms. Modulation of the atomic spin direction with an oscillating magnetic field shifts the detected signal to high frequencies. Using a fiber-coupled distributed feedback laser, we achieve magnetic field sensitivity of $7\text{ }\text{fT}/\sqrt{\text{Hz}}$ with a miniature $5\ifmmode\times\else\texttimes\fi{}5\ifmmode\times\else\texttimes\fi{}5\text{ }\text{mm}\text{ }\text{Rb}$ vapor cell.

arXiv:0903.2447•Physical Review A•Jul 24, 2009•273 citations

[The Measuring Method of Atomic Polarization of Alkali Metal Vapor Based on Optical Rotation and the Analysis of the Influence Factors].

Huining Shang, Wei Quan, Yao Chen +2 more

High sensitivity measurements of inertia and magnetic field could be achieved by utilizing a category of devices, which manipulate the atomic spins in the spin-exchange-relaxation-free regime. The alkali cell which contains the alkali metal vapor is used to sense magnetic field and inertia. The atomic number density of alkali vapor and the polarization of alkali metal vapor are two of the most important parameters of the cell. They play an important role in the research on atomic spins in the spin-exchange-relaxation-free regime. Besides, optical polarization plays an important role in quantum computing and atomic physics. We propose a measurement of alkali vapor polarization and alkali number density by detecting the optical rotation in one system. This method simplifies existing experimental equipment and processes. A constant bias magnetic field is applied and the Faraday rotation angle is detected by a bunch of the probe beam to deduce alkali-metal density. Then the magnetic field is closed and a bunch of the pump laser is utilized to polarize alkali-metal. Again, the probe beam is utilized to obtain the polarization of alkali metal. The alkali density obtained at first is used to deduce the polarization. This paper applies a numerical method to analyze the Faraday rotation and the polarization rotation. According to the numerical method, the optimal wavelength for the experiment is given. Finally, the fluctuation of magnetic field and wavelength on signal analysis are analyzed.

•Feb 1, 2016•2 citations

Faraday rotation and ellipticity spectroscopy between excited states of Rb vapor: Theory and experiment

Chenxu Liu, Yalong Hai, Anhong Dang

The Faraday rotation and ellipticity spectra of rubidium $5{P}_{3/2}\ensuremath{\rightarrow}4{D}_{5/2}$ transition in a magnetic field have been calculated and experimentally measured. By using the rotating quarter-wave plate method, the Stokes parameters of the $5{P}_{3/2}\ensuremath{\rightarrow}4{D}_{5/2}$ near-resonant probe light are measured to obtain the Faraday rotation and the ellipticity. The variation of the rotation and the ellipticity spectra is analyzed in different magnetic fields, temperatures, and pump powers. The polarization rotation over 50 deg in 1529 nm with negligible elliptical distortion is obtained. Our study of the Faraday effect between excited states of atoms broadens the available wavelength of the Faraday effect in applications.

Physical Review A•May 10, 2023•5 citations

Effect of optical polarization error on the magnetic resonance signal of NMOR atomic magnetometer

Mengnan Tian, Yanchao Chai, Zhenglong Lu +2 more

Abstract In NMOR magnetometers, we choose the linear polarized light to pump atoms, and the polarization state is the key factor affecting the evolution of alkali metal atoms. However, polarization errors are introduced due to the refraction of the glass surfaces of the cell and the imperfection of optical devices, which causes the actual laser light to be elliptically polarized. In this paper, the optical ellipticity for this system is accurately measured by the π transition principle first. Then, the magnetic resonance signals under different ellipticity are investigated theoretically and experimentally, and the atomic polarization state is visualized. The results show that the optical ellipticity error introduced by the system will reduce the measurement accuracy and sensitivity of the system, and it is meaningful to use high extinction ratio optical devices and introduce the quarter-wave plate to offset the circularly polarized components.

Journal of Physics Conference Series•Feb 1, 2025•0 citations

Analysis of Polarization Parameters of Co-Magnetometers Based on Elliptically Polarized Light Absorption Model

Lele Ma, Z X Liu, Xinhui Liu +3 more

The spin-exchange relaxation-free (SERF) comagnetometers, owing to their ultra-high sensitivity, are widely applied in fields such as inertial and magnetic field measurements, frontier physics research, etc. This technology relies on pump light to achieve the spin polarization of alkali metal atoms. During this process, the pump light is absorbed and thus attenuated by the alkali metal atoms. In this study, an absorption decay model for elliptically polarized light was solved by the fourth-order Runge-Kutta method, breaking through the applicability limitations of conventional analytical solutions for arbitrary polarized light. The effects of pump light polarization states and power on optical pumping rate, electron polarization, and measurement sensitivity were further investigated. It was found that there is a contradiction in achieving low polarization gradient and high scale coefficient by adjusting light intensity, increasing the pump light intensity can reduce the polarization gradient but will decrease the scale coefficient. Elliptically polarized light can realize low polarization gradient while enhancing the magnetic field response. This research establishes a theoretical foundation for optimizing the selection of pump light parameters in quantum sensors.

IEEE International Conference on Electronic Measurement & Instruments•Aug 22, 2025•0 citations
Optically pumped alkali metal atoms currently provide a sensitive solution for magnetic microscopic measurements. As the most practicable plan, Faraday rotation of linearly polarized light is extensively used in spin polarization measurements of alkali metal atoms. In some cases, near-resonant Faraday rotation is applied to improve the sensitivity. However, the near-resonant linearly polarized probe light is elliptically polarized after passing through optically pumped alkali metal vapor. The ellipticity of transmitted near-resonant probe light is numerically calculated and experimentally measured. In addition, we also analyze the negative impact of elliptical polarization on Faraday rotation measurements. From our theoretical estimate and experimental results, the elliptical polarization forms an inevitable error in spin polarization measurements.
A new method to measure the spin polarization of optically pumped alkali-metal atoms is demonstrated. Unlike the conventional method using far-detuned probe light, the near-resonant light with two specific frequencies was chosen. Because the Faraday rotation angle of this approach can be two orders of magnitude greater than that with the conventional method, this approach is more sensitive to the spin polarization. Based on the results of the experimental scheme, the spin polarization measurements are found to be in good agreement with the theoretical predictions, thereby demonstrating the feasibility of this approach.
Spin-exchange relaxation free alkali-metal magnetometers typically operate in the regime of high optical density, presenting challenges for simple and efficient optical pumping and detection. We describe a high-sensitivity Rb magnetometer using a single elliptically polarized off-resonant laser beam. Circular component of the light creates relatively uniform spin polarization while the linear component is used to measure optical rotation generated by the atoms. Modulation of the atomic spin direction with an oscillating magnetic field shifts the detected signal to high frequencies. Using a fiber-coupled distributed feedback laser, we achieve magnetic field sensitivity of 7 fT/Hz7\text{ }\text{fT}/\sqrt{\text{Hz}}7 fT/Hz​ with a miniature $5\ifmmode\times\else\texttimes\fi{}5\ifmmode\times\else\texttimes\fi{}5\text{ }\text{mm}\text{ }\text{Rb}$ vapor cell.
High sensitivity measurements of inertia and magnetic field could be achieved by utilizing a category of devices, which manipulate the atomic spins in the spin-exchange-relaxation-free regime. The alkali cell which contains the alkali metal vapor is used to sense magnetic field and inertia. The atomic number density of alkali vapor and the polarization of alkali metal vapor are two of the most important parameters of the cell. They play an important role in the research on atomic spins in the spin-exchange-relaxation-free regime. Besides, optical polarization plays an important role in quantum computing and atomic physics. We propose a measurement of alkali vapor polarization and alkali number density by detecting the optical rotation in one system. This method simplifies existing experimental equipment and processes. A constant bias magnetic field is applied and the Faraday rotation angle is detected by a bunch of the probe beam to deduce alkali-metal density. Then the magnetic field is closed and a bunch of the pump laser is utilized to polarize alkali-metal. Again, the probe beam is utilized to obtain the polarization of alkali metal. The alkali density obtained at first is used to deduce the polarization. This paper applies a numerical method to analyze the Faraday rotation and the polarization rotation. According to the numerical method, the optimal wavelength for the experiment is given. Finally, the fluctuation of magnetic field and wavelength on signal analysis are analyzed.
The Faraday rotation and ellipticity spectra of rubidium $5{P}_{3/2}\ensuremath{\rightarrow}4{D}_{5/2}$ transition in a magnetic field have been calculated and experimentally measured. By using the rotating quarter-wave plate method, the Stokes parameters of the $5{P}_{3/2}\ensuremath{\rightarrow}4{D}_{5/2}$ near-resonant probe light are measured to obtain the Faraday rotation and the ellipticity. The variation of the rotation and the ellipticity spectra is analyzed in different magnetic fields, temperatures, and pump powers. The polarization rotation over 50 deg in 1529 nm with negligible elliptical distortion is obtained. Our study of the Faraday effect between excited states of atoms broadens the available wavelength of the Faraday effect in applications.
Abstract In NMOR magnetometers, we choose the linear polarized light to pump atoms, and the polarization state is the key factor affecting the evolution of alkali metal atoms. However, polarization errors are introduced due to the refraction of the glass surfaces of the cell and the imperfection of optical devices, which causes the actual laser light to be elliptically polarized. In this paper, the optical ellipticity for this system is accurately measured by the π transition principle first. Then, the magnetic resonance signals under different ellipticity are investigated theoretically and experimentally, and the atomic polarization state is visualized. The results show that the optical ellipticity error introduced by the system will reduce the measurement accuracy and sensitivity of the system, and it is meaningful to use high extinction ratio optical devices and introduce the quarter-wave plate to offset the circularly polarized components.
The spin-exchange relaxation-free (SERF) comagnetometers, owing to their ultra-high sensitivity, are widely applied in fields such as inertial and magnetic field measurements, frontier physics research, etc. This technology relies on pump light to achieve the spin polarization of alkali metal atoms. During this process, the pump light is absorbed and thus attenuated by the alkali metal atoms. In this study, an absorption decay model for elliptically polarized light was solved by the fourth-order Runge-Kutta method, breaking through the applicability limitations of conventional analytical solutions for arbitrary polarized light. The effects of pump light polarization states and power on optical pumping rate, electron polarization, and measurement sensitivity were further investigated. It was found that there is a contradiction in achieving low polarization gradient and high scale coefficient by adjusting light intensity, increasing the pump light intensity can reduce the polarization gradient but will decrease the scale coefficient. Elliptically polarized light can realize low polarization gradient while enhancing the magnetic field response. This research establishes a theoretical foundation for optimizing the selection of pump light parameters in quantum sensors.