Breakdown of Angular Momentum Selection Rules in High Pressure Optical Pumping Experiments

Lancor, Brian; Babcock, Earl; Wyllie, Robert; Walker, Thad

doi:10.1103/physrevlett.105.083003

Cited by 13 publications

(31 citation statements)

References 25 publications

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“…Using the Walkup parameterization is a simple & alternative way to account for the effect of off resonant absorption, which was first pointed out in Ref. [31]. We justify the use of this approach because it reliably reproduces the measured values of P ∞ as function of ν for a pure Rb cell reported in Ref.…”

Section: The Alkali X-factorsmentioning

confidence: 86%

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Development of high-performance alkali-hybrid polarizedHe3targets for electron scattering

et al. 2015

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We present the development of high-performance polarized 3 He targets for use in electron scattering experiments that utilize the technique of alkali-hybrid spin-exchange optical pumping. We include data obtained during the characterization of 24 separate target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. The results presented here document dramatic improvement in the performance of polarized 3 He targets, as well as the target properties and operating parameters that made those improvements possible. Included in our measurements were determinations of the so-called X-factors that quantify a temperature-dependent and as-yet poorly understood spin-relaxation mechanism that limits the maximum achievable 3 He polarization to well under 100%. The presence of this spinrelaxation mechanism was clearly evident in our data. We also present results from a simulation of the alkali-hydrid spin-exchange optical pumping process that was developed to provide guidance in the design of these targets. Good agreement with actual performance was obtained by including details such as off-resonant optical pumping. Now benchmarked against experimental data, the simulation is useful for the design of future targets. Included in our results is a measurement of the K-3 He spin-exchange rate coefficient k K se = (7.46 ± 0.62)×10 −20 cm 3 /s over the temperature range 503 K to 563 K.

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Section: The Alkali X-factorsmentioning

confidence: 86%

“…where we've assumed pumping with perfectly monochromatic light with frequency ν. Measurements by Romalis et al [20] and more recently by Lancor et al [31][32][33] indicate that |T d | is of order 0.1 ps for alkali-3 He collisions. Using this value, we find that (3σ 3 .…”

Section: The Alkali X-factorsmentioning

confidence: 99%

Development of high-performance alkali-hybrid polarizedHe3targets for electron scattering

et al. 2015

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“…Atoms that return to the m S =1/2 state only rarely absorb the polarized light, while those that return to m S = −1/2 will be efficiently re-excited. In this manner atoms will preferentially populate the m S =1/2 state, reaching a steady-state population of P ∞ (Lancor et al , 2010a). …”

Section: Spin-exchange Optical Pumpingmentioning

confidence: 99%

Optically polarizedHe3

et al. 2017

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This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements.

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“…The spectral bandwidth of high-power diodes typically spreads over the range of 3-5 nm. A narrower emission spectrum in the range of 0.1-0.5 nm and a smaller wavelength tolerance can be extremely beneficial for special applications such as spin exchange optical pumping (SEOP) [1], which is of great importance in the fields of nuclear physics [2], atomic physics [3], laser cooling [4], and neutron scattering [5].…”

Section: Introductionmentioning

confidence: 99%

Development of stable, narrow spectral line-width, fiber delivered laser source for spin exchange optical pumping

et al. 2015

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We developed a stable, narrow spectral line-width, fiber delivered laser source for spin exchange optical pumping. An optimized external cavity equipped with an off-the-shelf volume holographic grating narrowed the spectral line-width of a 100 W high-power diode laser and stabilized the laser spectrum. The laser spectrum showed a high side mode suppression ratio of >30 dB and good long-term stability (center wavelength drifting within ±0.002 nm during 220 h of operation). Our laser is delivered by a multimode fiber with power ~70 W, center wavelength of 794.77 nm, and spectral bandwidth of ~0.12 nm.

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Breakdown of Angular Momentum Selection Rules in High Pressure Optical Pumping Experiments

Cited by 13 publications

References 25 publications

Development of high-performance alkali-hybrid polarizedHe3targets for electron scattering

Development of high-performance alkali-hybrid polarizedHe3targets for electron scattering

Optically polarizedHe3

Development of stable, narrow spectral line-width, fiber delivered laser source for spin exchange optical pumping

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