Measurement of rubidium vapor number density based on Faraday modulator

Shang, Huining; Zhou, Binquan; Quan, Wei; Chi, Haotian; Fang, Jiancheng; Zou, Sheng

doi:10.1088/1361-6463/ac71e3

Cited by 7 publications

(3 citation statements)

References 30 publications

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“…Figure 4 shows experimentally measured [Rb] lower than [Rb] sat for most T oven investigated. This is similar to Shao et al [41] and Shang et al [55] who both observed lower than saturation Rb vapor densities over a range of temperatures. Adsorption of alkali metal to glass walls has been suggested as a mechanism for lower alkali metal vapor densities [56].…”

Section: Closed Cell Rb Density For Different Oven Temperaturessupporting

confidence: 90%

Investigating Rubidium Density and Temperature Distributions in a High-Throughput 129Xe-Rb Spin-Exchange Optical Pumping Polarizer

2022

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Accurate knowledge of the rubidium (Rb) vapor density, [Rb], is necessary to correctly model the spin dynamics of 129Xe-Rb spin-exchange optical pumping (SEOP). Here we present a systematic evaluation of [Rb] within a high-throughput 129Xe-Rb hyperpolarizer during continuous-flow SEOP. Near-infrared (52S1/2→52P1/2 (D1)/52P3/2 (D2)) and violet (52S1/2→62P1/2/62P3/2) atomic absorption spectroscopy was used to measure [Rb] within 3.5 L cylindrical SEOP cells containing different spatial distributions and amounts of Rb metal. We were able to quantify deviation from the Beer-Lambert law at high optical depth for D2 and 62P3/2 absorption by comparison with measurements of the D1 and 62P1/2 absorption lines, respectively. D2 absorption deviates from the Beer-Lambert law at [Rb]D2>4×1017 m−3 whilst 52S1/2→62P3/2 absorption deviates from the Beer-Lambert law at [Rb]6P3/2>(4.16±0.01)×1019 m−3. The measured [Rb] was used to estimate a 129Xe-Rb spin exchange cross section of γ′=(1.2±0.1)×10−21 m3 s−1, consistent with spin-exchange cross sections from the literature. Significant [Rb] heterogeneity was observed in a SEOP cell containing 1 g of Rb localized at the back of the cell. While [Rb] homogeneity was improved for a greater surface area of the Rb source distribution in the cell, or by using a Rb presaturator, the measured [Rb] was consistently lower than that predicted by saturation Rb vapor density curves. Efforts to optimize [Rb] and thermal management within spin polarizer systems are necessary to maximize potential future enhancements of this technology.

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Section: Closed Cell Rb Density For Different Oven Temperaturessupporting

confidence: 90%

Investigating Rubidium Density and Temperature Distributions in a High-Throughput 129Xe-Rb Spin-Exchange Optical Pumping Polarizer

2022

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“…Differences in the transition probabilities lead to polarization dependent absorption (dichroism) and continuous polarization state transformation (birefringence) as the light propagates through the vapor [75,76]. The Faraday geometry exhibits a circular birefringence as differential refraction of circular handed light causes magneto-optical rotation of the plane of linear light.…”

Section: Elliptical Birefringencementioning

confidence: 99%

Exploiting non-orthogonal eigenmodes in a non-Hermitian optical system to realize sub-100 MHz magneto-optical filters.

Logue¹,

Briscoe²,

Pizzey³

et al. 2023

Preprint

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Non-Hermitian physics is responsible for many of the counter-intuitive effects observed in optics research opening up new possibilities in sensing, polarization control and measurement. A hallmark of non-Hermitian matrices is the possibility of non-orthogonal eigenvectors resulting in coupling between modes. The advantages of propagation mode coupling have been little explored in magneto-optical filters and other devices based on birefringence. Magneto-optical filters select for ultra-narrow transmission regions by passing light through an atomic medium in the presence of a magnetic field. Passive filter designs have traditionally been limited by Doppler broadening of thermal vapors. Even for filter designs incorporating a pump laser, transmissions are typically less than 15% for sub-Doppler features. Here we exploit our understanding of non-Hermitian physics to induce non-orthogonal propagation modes in a vapor and realize better magneto-optical filters. We construct two new filter designs with ENBWs and maximum transmissions of 181 MHz, 42 % and 140 MHz, 17% which are the highest figure of merit and first sub-100 MHz FWHM passive filters recorded respectively. This work opens up a range of new filter applications including metrological devices for use outside a lab setting and commends filtering as a new candidate for deeper exploration of non-Hermitian physics such as exceptional points of degeneracy.

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“…This approach calculates alkali vapor density by analyzing the optical rotation angle generated as a linearly polarized light passes through the alkali metal vapor. [18][19][20] This method offers several advantages, particularly excelling in measuring alkali metal absorption spectrum in high-density conditions and accommodating measurements at various alkali vapor densities. However, it does necessitate the application of a high-intensity, uniform magnetic field during experiments, which adds complexity to the experimental setup and carries the potential risk of disrupting shielding functionality.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Rubidium Vapor Density Based on Spin‐Exchange Rate

Shang,

Zou,

Zhang

et al. 2024

Adv Quantum Tech

Self Cite

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An efficient method is proposed for quantifying rubidium vapor density by analyzing the spin‐exchange rate between alkali metals. This method effectively addresses two primary challenges in measuring alkali vapor density. First, it overcomes the limitation of absorption spectroscopy to measure vapor density under optically thick conditions, typically restricted to temperature higher than 420K, equivalent to alkali vapor density exceeding . Second, it mitigates the risk of disrupting shielding functionality due to the application of a strong magnetic field, often in the range of several tens of Gauss or higher, when employing the Faraday rotation for vapor‐density measurement. The spin‐exchange rate between atoms, inherently related to the vapor density, is evident in the electron‐paramagnetic‐resonance spectrum of spin‐polarized , thereby providing a possibility for measuring alkali vapor density. To eliminate overlap between two Lorentzian curves resulting from two decomposed components of an oscillating field, a small rotating magnetic field with identical amplitude and frequency but a 90‐degree phase shift along both the x and y axes is applied. This method is successfully employed to measure vapor density in the temperature range of 373–433 K, with the measured outcomes closely matching the saturation vapor curve.

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Measurement of rubidium vapor number density based on Faraday modulator

Cited by 7 publications

References 30 publications

Investigating Rubidium Density and Temperature Distributions in a High-Throughput 129Xe-Rb Spin-Exchange Optical Pumping Polarizer

Investigating Rubidium Density and Temperature Distributions in a High-Throughput 129Xe-Rb Spin-Exchange Optical Pumping Polarizer

Exploiting non-orthogonal eigenmodes in a non-Hermitian optical system to realize sub-100 MHz magneto-optical filters.

Measurement of Rubidium Vapor Density Based on Spin‐Exchange Rate

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