Light narrowing of rubidium magnetic-resonance lines in high-pressure optical-pumping cells

Appelt, Stephan; Baranga, A. Ben‐Amar; Young, A. R.; Happer, W.

doi:10.1103/physreva.59.2078

Cited by 134 publications

(100 citation statements)

References 24 publications

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“…At higher magnetic fields such as the Earth's field, it is possible to use a single SERF magnetometer as a 3-axis null-detector with external feedback [33]. The possibility of reducing spin-exchange relaxation in a finite magnetic field has also been explored [34]. The idea is to pump most atoms into a stretched state with m = I +1/2 where they cannot undergo spin-exchange collisions due to conservation of angular momentum.…”

Section: General Features and Limits Of Sensitivity Of Optical Mamentioning

confidence: 99%

Optical magnetometry

2007

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Some of the most sensitive methods of measuring magnetic fields utilize interactions of resonant light with atomic vapor. Recent developments in this vibrant field are improving magnetometers in many traditional areas such as measurement of geomagnetic anomalies and magnetic fields in space, and are opening the door to new ones, including, dynamical measurements of bio-magnetic fields, detection of nuclear magnetic resonance (NMR), magnetic-resonance imaging (MRI), inertialrotation sensing, magnetic microscopy with cold atoms, and tests of fundamental symmetries of Nature.

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Section: General Features and Limits Of Sensitivity Of Optical Mamentioning

confidence: 99%

Optical magnetometry

2007

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“…Such broadening can be completely eliminated for Zeeman resonances near zero magnetic field [5,6,7]. The broadening of the hyperfine and Zeeman resonances at a finite magnetic field can be reduced by optically pumping the atoms into a nearly fully polarized state [8,9,10]. These techniques have been used to demonstrate clock resonance narrowing [9] and have led to significant improvement in the sensitivity of atomic magnetometers [11] and to their application for detection of magnetic fields from the brain [12] and nuclear quadrupole resonance signals from explosives [13].…”

Section: Introductionmentioning

confidence: 99%

“…Here we focus on the regime of light-narrowing [8,10], with R se ≫ R op ≫ R sd , which also implies that P is close to unity. For weak rf excitation an analytic expression for T 2 under these conditions has been obtained in [8,10,25],…”

Section: B Modified Bementioning

confidence: 99%

“…Here we study experimentally and theoretically the effects of SE collisions in an atomic magnetometer operating in geomagnetic field range. It was shown in [8,9,10] that in the limit of weak excitation the Zeeman and hyperfine resonance linewidths can be reduced from ∆ω ∼ R se , where R se is the alkali-metal SE rate, to ∆ω ∼ (R se R sd ) 1/2 , where R sd is the alkali-metal spindestruction rate, by pumping most of the atoms into the stretched spin state with maximum angular momentum. Since for alkali-metal atoms R sd ≪ R se (for example, for K atoms R sd ∼ 10 −4 R se ), this technique can reduce the resonance linewidth by a factor of 10 − 100.…”

Section: Introductionmentioning

confidence: 99%

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Low-noise high-density alkali-metal scalar magnetometer

et al. 2009

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We present an experimental and theoretical study of a scalar atomic magnetometer using an oscillating field-driven Zeeman resonance in a high-density optically-pumped potassium vapor. We describe an experimental implementation of an atomic gradiometer with a noise level below 10 fT Hz −1/2 , fractional field sensitivity below 10 −9 Hz −1/2 , and an active measurement volume of about 1.5 cm 3 . We show that the fundamental field sensitivity of a scalar magnetometer is determined by the rate of alkali-metal spin-exchange collisions even though the resonance linewidth can be made much smaller than the spin-exchange rate by pumping most atoms into a stretched spin state.

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“…For a Gaussian laser profile with a width of ␦ l the optical pumping rate R depends on the photon flux F in the following way: 13 Rϭ 2ͱ ln 2r e f l 3 wЈ͑r,s ͒…”

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Experimental studies of rubidium absolute polarization at high temperatures

Appelt

Ünlü

Zilles

et al. 1999

Applied Physics Letters

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We report on measurements of the absolute rubidium ͑Rb͒ polarization, optically pumped by a high-power diode laser array, up to temperatures of 180°C. The penetration of the pump laser light into a high-pressure cell has been studied experimentally and theoretically. The experimental results are compared to a model, which describes the local Rb polarization and optical pumping rate in the cell. © 1999 American Institute of Physics. ͓S0003-6951͑99͒03229-5͔In nuclear magnetic resonance and in other fields of science such as human MRI, 1-4 material and surface physics, 5,6 the production of hyperpolarized noble gases through spin exchange with optically pumped alkali-metal atoms has gained importance. For some potential applications such as 129 Xe brain imaging, 4 very high nuclear polarizations are required to circumvent the limitations of the delivery method 7 and to avoid the anaesthetic effects of large quantities of Xe in the brain.We have built a Rb-Xe hyperpolarizing unit, similar to that described by Driehuys et al.,8 for the production of several grams of polarized Xe ice. In order to optimize the Rb ͑and thus Xe͒ polarization, a low-cost and compact polarization imaging device was developed which enables measurement of the distribution of the absolute Rb polarization in the pumping cell. The methodology and first experimental results of absolute Rb polarization imaging in high-pressure optical pumping cells at a temperature of Tϭ100°C were recently published by Baranga et al. 9 and Young et al. 10 Spin exchange optical pumping at temperatures higher than 100°C causes the spin exchange rate between Rb and Xe to be larger and therefore the time required to polarize Xe atoms is significantly shorter.Experimental results of the absolute 85 Rb polarization in high pressure optical pumping cells for temperatures up to 180°C are presented. The measured, volume-averaged absolute Rb polarization sets a limit on the maximum achievable Xe nuclear polarization at high temperatures. Furthermore, we studied the penetration of the pump laser light into the cell at a temperature range from 120-180°C. Figure 1 shows a schematic diagram of the compact, low-cost 85 Rb polarization imaging unit. For the sake of clarity, components of the Rb-Xe polarizer necessary for operating in a flowing mode and to freeze out the Xe gas are not shown. The optical pumping cell consisted of a glass cylinder with flat glass windows in order to avoid lens effects on the pump laser beam. The cell ͑inner diameter 24 mm, length 70 mm͒ was filled with approximately 1 g of Rb, 7 atm of 4 He, and 0.07 atm of N 2 and Xe gas. For optical pumping parallel to the magnetic field B 0 (z axis͒, we use a fiberoptically coupled diode laser array ͑Opto Power Corp., OPC 100͒ with a maximum output power of 100 W and a linewidth of 2 nm. The absolute 85 Rb polarization was measured by detecting, optically in the transverse mode, the Zeeman transitions of 85 Rb in a high magnetic field. The Zeeman spectrum was obtained by sweeping the magnetic field B 0 from 53....

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Light narrowing of rubidium magnetic-resonance lines in high-pressure optical-pumping cells

Cited by 134 publications

References 24 publications

Optical magnetometry

Optical magnetometry

Low-noise high-density alkali-metal scalar magnetometer

Experimental studies of rubidium absolute polarization at high temperatures

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