Optimizations of spin-exchange relaxation-free magnetometer based on potassium and rubidium hybrid optical pumping.

The hybrid optical pumping atomic magnetometers have not realized its theoretical sensitivity, the optimization is critical for optimal performance. The optimizations proposed in this paper are suitable for hybrid optical pumping atomic magnetometer, which contains two alkali species. To optimize the parameters, the dynamic equations of spin evolution with two alkali species were solved, whose steady-state solution is used to optimize the parameters. The demand of the power of the pump beam is large for hybrid optical pumping. Moreover, the sensitivity of the hybrid optical pumping magnetometer increases with the increase of the power density of the pump beam. The density ratio between the two alkali species is especially important for hybrid optical pumping magnetometer. A simple expression for optimizing the density ratio is proposed in this paper, which can help to determine the mole faction of the alkali atoms in fabricating the hybrid cell before the cell is sealed. The spin-exchange rate between the two alkali species is proportional to the saturated density of the alkali vapor, which is highly dependent on the temperature of the cell. Consequently, the sensitivity of the hybrid optical pumping magnetometer is dependent on the temperature of the cell. We proposed the thermal optimization of the hybrid cell for a hybrid optical pumping magnetometer, which can improve the sensitivity especially when the power of the pump beam is low. With these optimizations, a sensitivity of approximately 5 fT/Hz(1/2) is achieved with gradiometer arrangement.

[1]  Tao Wang,et al.  In situ magnetic compensation for potassium spin-exchange relaxation-free magnetometer considering probe beam pumping effect. , 2014, The Review of scientific instruments.

[2]  H. Ohnishi,et al.  Effect of Spatial Homogeneity of Spin Polarization on Magnetic Field Response of an Optically Pumped Atomic Magnetometer Using a Hybrid Cell of K and Rb Atoms , 2012, IEEE Transactions on Magnetics.

[3]  Jiancheng Fang,et al.  In situ triaxial magnetic field compensation for the spin-exchange-relaxation-free atomic magnetometer. , 2012, The Review of scientific instruments.

[4]  L. Trahms,et al.  Magnetoencephalography with a chip-scale atomic magnetometer , 2012, Biomedical optics express.

[5]  Keigo Kamada,et al.  Sensitivity Improvement of Spin-Exchange Relaxation Free Atomic Magnetometers by Hybrid Optical Pumping of Potassium and Rubidium , 2011, IEEE Transactions on Magnetics.

[6]  T. Walker,et al.  Polarization limits in K-Rb spin-exchange mixtures , 2011, 1104.4956.

[7]  M. Romalis,et al.  Hybrid optical pumping of optically dense alkali-metal vapor without quenching gas. , 2010, Physical review letters.

[8]  A. C. Maloof,et al.  Ultrahigh sensitivity magnetic field and magnetization measurements with an atomic magnetometer , 2009, 0910.2206.

[9]  D. Budker,et al.  Spin-Exchange-Relaxation-Free Magnetometry with Cs Vapor , 2007, 0708.1012.

[10]  W. Gawlik,et al.  Sensitive optical magnetometry based on nonlinear magneto-optical rotation with amplitude-modulated light , 2007, 2007 European Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference.

[11]  T. W. Kornack,et al.  A low-noise ferrite magnetic shield , 2007 .

[12]  T. Walker,et al.  Spin-exchange optical pumping of 3He with Rb-K mixtures and pure K , 2007 .

[13]  D. Hoffman,et al.  Magnetoencephalography with an atomic magnetometer , 2006 .

[14]  D. Budker,et al.  Robust, high-speed, all-optical atomic magnetometer , 2006, physics/0609041.

[15]  Michael V. Romalis,et al.  Unshielded three-axis vector operation of a spin-exchange-relaxation-free atomic magnetometer , 2004 .

[16]  Bastiaan Driehuys,et al.  Hybrid spin-exchange optical pumping of 3He. , 2003, Physical review letters.

[17]  T. W. Kornack,et al.  A subfemtotesla multichannel atomic magnetometer , 2003, Nature.

[18]  M. Romalis,et al.  High-sensitivity atomic magnetometer unaffected by spin-exchange relaxation. , 2002, Physical review letters.

[19]  C. B. Alcock,et al.  Vapour Pressure Equations for the Metallic Elements: 298–2500K , 1984 .

[20]  N. Ressler,et al.  Measurement of Spin-Exchange Cross Sections for Cs 133 , Rb 87 , Rb 85 , K 39 , and Na 23 , 1969 .

[21]  Robert J. Hull,et al.  Spin-Exchange Cross Sections for Rb87-Rb87 and Rb87-Cs133 Collisions , 1967 .