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W Happer - One of the best experts on this subject based on the ideXlab platform.
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simple method of light shift suppression in Optical Pumping systems
arXiv: Atomic Physics, 2013Co-Authors: B H Mcguyer, Y Y Jau, W HapperAbstract:We report a simple method to suppress the light shift in Optical Pumping systems. This method uses only frequency modulation of a radio frequency or microwave source, which is used to excite an atomic resonance, to simultaneously lock the source frequency to the atomic resonance and lock the Pumping light frequency to suppress the light shift. We experimentally validate the method in a vapor-cell atomic clock and verify the results through numerical simulation. This technique can be applied to many Optical Pumping systems that experience light shifts. It is especially useful for atomic frequency standards because it improves long-term performance, reduces the influence of the laser, and requires less equipment than previous methods.
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Optical Pumping and spectroscopy of cs vapor at high magnetic field
Physical Review A, 2011Co-Authors: Ben A Olsen, Brian Patton, Yuanyu Jau, W HapperAbstract:We have measured changes in the ground-state populations of Cs vapor induced by Optical Pumping at high magnetic field. The $2.7$-T field of our experiments is strong enough to decouple the nuclear and electronic spins, allowing us to independently measure each population. The spatial dependence of the Cs populations in small amounts of buffer gas obeys a simple coupled diffusion model and the relative populations reveal the details of relaxation within the vapor cell. Optical Pumping can produce high nuclear polarization in the Cs vapor due to perturbations of the hyperfine interaction during collisions with buffer-gas particles and depending on the Pumping transition, radiation trapping can strongly influence the electronic and nuclear polarizations in the vapor.
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push pull Optical Pumping of pure superposition states
Physical Review Letters, 2004Co-Authors: Yuanyu Jau, Eli Miron, A B Post, N N Kuzma, W HapperAbstract:A new Optical Pumping method, "push-pull Pumping," can produce very nearly pure, coherent superposition states between the initial and the final sublevels of the important field-independent 0-0 clock resonance of alkali-metal atoms. The key requirement for push-pull Pumping is the use of D1 resonant light which alternates between left and right circular polarization at the Bohr frequency of the state. The new Pumping method works for a wide range of conditions, including atomic beams with almost no collisions, and atoms in buffer gases with pressures of many atmospheres.
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light narrowing of rubidium magnetic resonance lines in high pressure Optical Pumping cells
Physical Review A, 1999Co-Authors: S Appelt, Benamar A Baranga, A R Young, W HapperAbstract:We report on some unusual magnetic-resonance phenomena of Optically pumped Rb vapor in high-pressure gas cells. When Rb-Rb spin exchange is the fastest spin-relaxation rate, we observe a considerable narrowing of the magnetic-resonance linewidths with increasing pump-laser power. The experimentally measured Rb magnetic-resonance linewidths are in excellent agreement with a theoretical model, which includes the processes of Rb-He and Rb-Xe spin destruction, Rb-Rb spin exchange, and Rb Optical Pumping.
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theory of spin exchange Optical Pumping of 3 he and 129 xe
Physical Review A, 1998Co-Authors: S Appelt, Benamar A Baranga, A R Young, C J Erickson, M V Romalis, W HapperAbstract:We present a comprehensive theory of nuclear spin polarization of ${}^{3}\mathrm{He}$ and ${}^{129}\mathrm{Xe}$ gases by spin-exchange collisions with Optically pumped alkali-metal vapors. The most important physical processes considered are (1) spin-conserving spin-exchange collisions between like or unlike alkali-metal atoms; (2) spin-destroying collisions of the alkali-metal atoms with each other and with buffer-gas atoms; (3) electron-nuclear spin-exchange collisions between alkali-metal atoms and ${}^{3}\mathrm{He}$ or ${}^{129}\mathrm{Xe}$ atoms; (4) spin interactions in van der Waals molecules consisting of a Xe atom bound to an alkali-metal atom; (5) Optical Pumping by laser photons; (6) spatial diffusion. The static magnetic field is assumed to be small enough that the nuclear spin of the alkali-metal atom is well coupled to the electron spin and the total spin is very nearly a good quantum number. Conditions appropriate for the production of large quantities of spin-polarized ${}^{3}\mathrm{He}$ or ${}^{129}\mathrm{Xe}$ gas are assumed, namely, atmospheres of gas pressure and nearly complete quenching of the Optically excited alkali-metal atoms by collisions with ${\mathrm{N}}_{2}$ or ${\mathrm{H}}_{2}$ gas. Some of the more important results of this work are as follows: (1) Most of the Pumping and relaxation processes are sudden with respect to the nuclear polarization. Consequently, the steady-state population distribution of alkali-metal atoms is well described by a spin temperature, whether the rate of spin-exchange collisions between alkali-metal atoms is large or small compared to the Optical Pumping rate or the collisional spin-relaxation rates. (2) The population distributions that characterize the response to sudden changes in the intensity of the Pumping light are not described by a spin temperature, except in the limit of very rapid spin exchange. (3) Expressions given for the radio-frequency (rf) resonance linewidths and areas can be used to make reliable estimates of the local spin polarization of the alkali-metal atoms. (4) Diffusion effects for these high-pressure conditions are mainly limited to thin layers at the cell surface and at internal resonant surfaces generated by radio-frequency magnetic fields when the static magnetic field has substantial spatial inhomogeneities. The highly localized effects of diffusion at these surfaces are described with closed-form analytic functions instead of the spatial eigenmode expansions that are appropriate for lower-pressure cells.
T G Walker - One of the best experts on this subject based on the ideXlab platform.
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breakdown of angular momentum selection rules in high pressure Optical Pumping experiments
Physical Review Letters, 2010Co-Authors: Brian Lancor, E Babcock, Robert Wyllie, T G WalkerAbstract:We present measurements, by using two complementary methods, of the breakdown of atomic angular momentum selection rules in He-broadened Rb vapor. Atomic dark states are rendered weakly absorbing due to fine-structure mixing during Rb-He collisions. The effect substantially increases the photon demand for Optical Pumping of dense vapors.
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spin exchange Optical Pumping of 3he with rb k mixtures and pure k
Physical Review A, 2007Co-Authors: W C Chen, T G Walker, T R Gentile, E BabcockAbstract:We have studied the efficiency of spin-exchange Optical Pumping SEOP in cells that contain either pure rubidium, mixtures of rubidium and potassium, or pure potassium. Optical Pumping was performed with spectrally narrowed diode array lasers operating at either the wavelength of the Rb 5s1/2-5p1/2 transition 795 nm or the K 4s1/2-4p1/2 transition 770 nm. Calculations of the expected efficiency are shown for practical conditions and compared to measurements. We have measured the vapor density ratio in Rb-K mixture cells using absorption of white light. Our focus is on the conditions that are relevant for neutron spin filters, but the results are relevant to all applications of SEOP. We find that both Rb-K and pure K cells yield improvements in the spin-exchange efficiency, and each approach has its own advantages. Overall, the best results for high polarizing rate with high polarization were obtained with mixture cells with K-Rb vapor density ratios between 2 and 6.
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spin exchange Optical Pumping of he 3 with rb k mixtures and pure k
Physical Review A, 2007Co-Authors: W C Chen, T G Walker, T R Gentile, E BabcockAbstract:We have studied the efficiency of spin-exchange Optical Pumping SEOP in cells that contain either pure rubidium, mixtures of rubidium and potassium, or pure potassium. Optical Pumping was performed with spectrally narrowed diode array lasers operating at either the wavelength of the Rb 5s1/2-5p1/2 transition 795 nm or the K 4s1/2-4p1/2 transition 770 nm. Calculations of the expected efficiency are shown for practical conditions and compared to measurements. We have measured the vapor density ratio in Rb-K mixture cells using absorption of white light. Our focus is on the conditions that are relevant for neutron spin filters, but the results are relevant to all applications of SEOP. We find that both Rb-K and pure K cells yield improvements in the spin-exchange efficiency, and each approach has its own advantages. Overall, the best results for high polarizing rate with high polarization were obtained with mixture cells with K-Rb vapor density ratios between 2 and 6.
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spin exchange Optical Pumping using a frequency narrowed high power diode laser
Applied Physics Letters, 2000Co-Authors: Ian A Nelson, Bien Chann, T G WalkerAbstract:We describe a method for frequency narrowing commercial high power diode lasers from 2 to 0.1 nm bandwidth with modest loss of power (<2 dB). The resulting laser light is well suited for spin-exchange Optical Pumping, and we demonstrate that the polarization produced by a 2.5 W narrowband laser exceeds that of a 15 W array by 40% in our Optical Pumping system.
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spin exchange Optical Pumping of noble gas nuclei
Reviews of Modern Physics, 1997Co-Authors: T G Walker, W HapperAbstract:Spin-exchange Optical Pumping of mixtures of alkali-metal vapors and noble gases can be used to efficiently polarize the nuclei of the noble-gas atoms. Liters of noble gases at standard temperature and pressure and with nuclear spin polarizations of several tens of percent are now used in many applications. The authors describe the basic phenomena that govern the spin-exchange process and review the physics of angular momentum transfer and loss in Optical Pumping and spin-exchange collisions.
Jianhua Liu - One of the best experts on this subject based on the ideXlab platform.
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the polarization and the fundamental sensitivity of 39 k 133 cs 85 rb 4 he hybrid Optical Pumping spin exchange relaxation free atomic magnetometers
Scientific Reports, 2017Co-Authors: Jiancheng Fang, Jianhua Liu, Dongyang Jing, Liangliang Wang, Wei Quan, Wuming LiuAbstract:The hybrid Optical Pumping spin exchange relaxation free (SERF) atomic magnetometers can realize ultrahigh sensitivity measurement of magnetic field and inertia. We have studied the 85Rb polarization of two types of hybrid Optical Pumping SERF magnetometers based on 39K-85Rb-4He and 133Cs-85Rb-4He respectively. Then we found that 85Rb polarization varies with the number density of buffer gas 4He and quench gas N2, Pumping rate of pump beam and cell temperature respectively, which will provide an experimental guide for the design of the magnetometer. We obtain a general formula on the fundamental sensitivity of the hybrid Optical Pumping SERF magnetometer due to shot-noise. The formula describes that the fundamental sensitivity of the magnetometer varies with the number density of buffer gas and quench gas, the Pumping rate of pump beam, external magnetic field, cell effective radius, measurement volume, cell temperature and measurement time. We obtain a highest fundamental sensitivity of 1.5073 aT/Hz 1/2 (1 aT = 10−18 T) with 39K-85Rb-4He magnetometer between above two types of magnetometers when 85Rb polarization is 0.1116. We estimate the fundamental sensitivity limit of the hybrid Optical Pumping SERF magnetometer to be superior to 1.8359 × 10−2 aT/Hz 1/2, which is higher than the shot-noise-limited sensitivity of 1 aT/Hz 1/2 of K SERF atomic magnetometer.
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the polarization and the fundamental sensitivity of 39 k 133 cs 85 rb 4 he hybrid Optical Pumping spin exchange relaxation free atomic magnetometers
arXiv: Atomic Physics, 2017Co-Authors: Jiancheng Fang, Jianhua Liu, Dongyang Jing, Liangliang Wang, Wei Quan, Wuming LiuAbstract:The hybrid Optical Pumping spin exchange relaxation free (SERF) atomic magnetometers can realize ultrahigh sensitivity measurement of magnetic field and inertia. We have studied the $^{\text{85}}$Rb polarization of two types of hybrid Optical Pumping SERF magnetometers based on $^{\text{39}}$K-$^{\text{85}}$Rb-$^{\text{4}}$He and $^{\text{133}}$Cs-$^{\text{85}}$Rb-$^{\text{4}}$He respectively. Then we found that $^{\text{85}}$Rb polarization varies with the number density of buffer gas $^{\text{4}}$He and quench gas N$_{\text{2}}$, Pumping rate of pump beam and cell temperature respectively, which will provide an experimental guide for the design of the magnetometer. We obtain a general formula on the fundamental sensitivity of the hybrid Optical Pumping SERF magnetometer due to shot-noise. The formula describes that the fundamental sensitivity of the magnetometer varies with the number density of buffer gas and quench gas, the Pumping rate of pump beam, external magnetic field, cell effective radius, measurement volume, cell temperature and measurement time. We obtain a highest fundamental sensitivity of $1.5073$ $aT/Hz^{1/2}$ ($1$ $aT=10^{-18}$ $T$) with $^{\text{39}}$K-$^{\text{85}}$Rb-$^{\text{4}}$He magnetometer between above two types of magnetometers when $^{\text{85}}$Rb polarization is $0.1116$. We estimate the fundamental sensitivity limit of the hybrid Optical Pumping SERF magnetometer to be superior to $1.8359\times10^{-2}$ $aT/Hz^{1/2}$, which is higher than the shot-noise-limited sensitivity of $1$ $aT/Hz^{1/2}$ of K SERF atomic magnetometer.
E Babcock - One of the best experts on this subject based on the ideXlab platform.
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breakdown of angular momentum selection rules in high pressure Optical Pumping experiments
Physical Review Letters, 2010Co-Authors: Brian Lancor, E Babcock, Robert Wyllie, T G WalkerAbstract:We present measurements, by using two complementary methods, of the breakdown of atomic angular momentum selection rules in He-broadened Rb vapor. Atomic dark states are rendered weakly absorbing due to fine-structure mixing during Rb-He collisions. The effect substantially increases the photon demand for Optical Pumping of dense vapors.
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effects of high flux neutron beams onh3ecells polarizedin situwith spin exchange Optical Pumping
Physical Review A, 2009Co-Authors: E Babcock, W C Chen, T R Gentile, S Boag, M Becker, T E Chupp, G L Jones, A K Petukhov, Torsten SoldnerAbstract:Polarized $^{3}\text{H}\text{e}$ produced by spin-exchange Optical Pumping (SEOP) has potential as a neutron spin filter for polarization and polarization analysis in many neutron-scattering and neutron particle physics applications. The advantage of the SEOP method is its suitability for providing continuous stable polarization over the course of long experiments. However, we have discovered that exposure to high neutron flux leads to additional strong relaxation mechanisms in the Optically polarized alkali-metal vapor used to polarize the $^{3}\text{H}\text{e}$. At a neutron flux density of $4.7\ifmmode\times\else\texttimes\fi{}{10}^{9}\text{ }{\text{cm}}^{\ensuremath{-}2}\text{ }{\text{s}}^{\ensuremath{-}1}$, the alkali-metal relaxation rate increased from 100 to $1000\text{ }{\text{s}}^{\ensuremath{-}1}$ leading to reduced alkali-metal polarization. Other effects such as time dependence and gas composition dependence were explored to help understand the processes. In this paper we discuss our observations and present possible solutions for practical use of SEOP as a neutron spin filter for high-flux density applications.
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spin exchange Optical Pumping of 3he with rb k mixtures and pure k
Physical Review A, 2007Co-Authors: W C Chen, T G Walker, T R Gentile, E BabcockAbstract:We have studied the efficiency of spin-exchange Optical Pumping SEOP in cells that contain either pure rubidium, mixtures of rubidium and potassium, or pure potassium. Optical Pumping was performed with spectrally narrowed diode array lasers operating at either the wavelength of the Rb 5s1/2-5p1/2 transition 795 nm or the K 4s1/2-4p1/2 transition 770 nm. Calculations of the expected efficiency are shown for practical conditions and compared to measurements. We have measured the vapor density ratio in Rb-K mixture cells using absorption of white light. Our focus is on the conditions that are relevant for neutron spin filters, but the results are relevant to all applications of SEOP. We find that both Rb-K and pure K cells yield improvements in the spin-exchange efficiency, and each approach has its own advantages. Overall, the best results for high polarizing rate with high polarization were obtained with mixture cells with K-Rb vapor density ratios between 2 and 6.
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spin exchange Optical Pumping of he 3 with rb k mixtures and pure k
Physical Review A, 2007Co-Authors: W C Chen, T G Walker, T R Gentile, E BabcockAbstract:We have studied the efficiency of spin-exchange Optical Pumping SEOP in cells that contain either pure rubidium, mixtures of rubidium and potassium, or pure potassium. Optical Pumping was performed with spectrally narrowed diode array lasers operating at either the wavelength of the Rb 5s1/2-5p1/2 transition 795 nm or the K 4s1/2-4p1/2 transition 770 nm. Calculations of the expected efficiency are shown for practical conditions and compared to measurements. We have measured the vapor density ratio in Rb-K mixture cells using absorption of white light. Our focus is on the conditions that are relevant for neutron spin filters, but the results are relevant to all applications of SEOP. We find that both Rb-K and pure K cells yield improvements in the spin-exchange efficiency, and each approach has its own advantages. Overall, the best results for high polarizing rate with high polarization were obtained with mixture cells with K-Rb vapor density ratios between 2 and 6.
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spin exchange Optical Pumping with alkali metal vapors
2005Co-Authors: E BabcockAbstract:While the method of Spin-exchange Optical Pumping, SEOP, of noble gases has existed since 1960 [Bouchiat60], many fundamental aspects of spin exchange Optical Pumping have gone largely unexplained. These questions included the values of the rate coefficients for spin-exchange, many aspects of the alkali-metal polarization and density inside the SEOP cells, the mechanisms of He wall relaxation, non-ideal values of the observed He polarization, and efficiency to produce it. This thesis describes the results of our efforts to quantity all parameters in SEOP and to begin to determine some of these unknowns. This thesis presents measurements of spin-exchange rate coefficients and efficiencies. A method to extend SEOP to multiple alkali species is presented. In addition, limits to the efficiency of Optical Pumping, the efficiency of spin-exchange, and the observed He polarization are explored.
Wuming Liu - One of the best experts on this subject based on the ideXlab platform.
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the polarization and the fundamental sensitivity of 39 k 133 cs 85 rb 4 he hybrid Optical Pumping spin exchange relaxation free atomic magnetometers
Scientific Reports, 2017Co-Authors: Jiancheng Fang, Jianhua Liu, Dongyang Jing, Liangliang Wang, Wei Quan, Wuming LiuAbstract:The hybrid Optical Pumping spin exchange relaxation free (SERF) atomic magnetometers can realize ultrahigh sensitivity measurement of magnetic field and inertia. We have studied the 85Rb polarization of two types of hybrid Optical Pumping SERF magnetometers based on 39K-85Rb-4He and 133Cs-85Rb-4He respectively. Then we found that 85Rb polarization varies with the number density of buffer gas 4He and quench gas N2, Pumping rate of pump beam and cell temperature respectively, which will provide an experimental guide for the design of the magnetometer. We obtain a general formula on the fundamental sensitivity of the hybrid Optical Pumping SERF magnetometer due to shot-noise. The formula describes that the fundamental sensitivity of the magnetometer varies with the number density of buffer gas and quench gas, the Pumping rate of pump beam, external magnetic field, cell effective radius, measurement volume, cell temperature and measurement time. We obtain a highest fundamental sensitivity of 1.5073 aT/Hz 1/2 (1 aT = 10−18 T) with 39K-85Rb-4He magnetometer between above two types of magnetometers when 85Rb polarization is 0.1116. We estimate the fundamental sensitivity limit of the hybrid Optical Pumping SERF magnetometer to be superior to 1.8359 × 10−2 aT/Hz 1/2, which is higher than the shot-noise-limited sensitivity of 1 aT/Hz 1/2 of K SERF atomic magnetometer.
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the polarization and the fundamental sensitivity of 39 k 133 cs 85 rb 4 he hybrid Optical Pumping spin exchange relaxation free atomic magnetometers
arXiv: Atomic Physics, 2017Co-Authors: Jiancheng Fang, Jianhua Liu, Dongyang Jing, Liangliang Wang, Wei Quan, Wuming LiuAbstract:The hybrid Optical Pumping spin exchange relaxation free (SERF) atomic magnetometers can realize ultrahigh sensitivity measurement of magnetic field and inertia. We have studied the $^{\text{85}}$Rb polarization of two types of hybrid Optical Pumping SERF magnetometers based on $^{\text{39}}$K-$^{\text{85}}$Rb-$^{\text{4}}$He and $^{\text{133}}$Cs-$^{\text{85}}$Rb-$^{\text{4}}$He respectively. Then we found that $^{\text{85}}$Rb polarization varies with the number density of buffer gas $^{\text{4}}$He and quench gas N$_{\text{2}}$, Pumping rate of pump beam and cell temperature respectively, which will provide an experimental guide for the design of the magnetometer. We obtain a general formula on the fundamental sensitivity of the hybrid Optical Pumping SERF magnetometer due to shot-noise. The formula describes that the fundamental sensitivity of the magnetometer varies with the number density of buffer gas and quench gas, the Pumping rate of pump beam, external magnetic field, cell effective radius, measurement volume, cell temperature and measurement time. We obtain a highest fundamental sensitivity of $1.5073$ $aT/Hz^{1/2}$ ($1$ $aT=10^{-18}$ $T$) with $^{\text{39}}$K-$^{\text{85}}$Rb-$^{\text{4}}$He magnetometer between above two types of magnetometers when $^{\text{85}}$Rb polarization is $0.1116$. We estimate the fundamental sensitivity limit of the hybrid Optical Pumping SERF magnetometer to be superior to $1.8359\times10^{-2}$ $aT/Hz^{1/2}$, which is higher than the shot-noise-limited sensitivity of $1$ $aT/Hz^{1/2}$ of K SERF atomic magnetometer.