Quenching cross sections for alkali-inert gas collisions

Speller, E.; Staudenmayer, B.; Kempter, V.

doi:10.1007/bf01408379

Cited by 33 publications

(18 citation statements)

References 27 publications

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“…Optical excitation here creates a non-equilibrium rovibrational distribution within the electronically excited state manifold and the Franck-Condon factors of the instantaneous distribution determine the observed spectroscopic signal. Interactions of an absorber with the environment can lead to relaxations, and for the case of atomic vapors it is known that collisions with rare gas atoms are extremely elastic [4].…”

Section: Introductionmentioning

confidence: 99%

Verifying thermodynamic equilibrium of molecular manifolds: Kennard-Stepanov spectroscopy of a molecular gas

et al. 2017

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The degree of thermalization of electronically excited state manifolds of an absorber can be tested via optical spectroscopy. In the thermalized manifolds case, the ratio of absorption and emission is expected to follow a universal Boltzmann-type frequency scaling, known as the Kennard-Stepanov relation. Here we investigate absorption and emission spectral profiles of rubidium, caesium and potassium molecular dimers in high pressure argon buffer gas environment and study the effect of collisionally induced redistribution. We find that, despite the use of nonlinear excitation techniques, the ratio of absorption and emission well follows the Kennard-Stepanov scaling for a variety of molecular transitions. We conclude that the upper electronic state rovibrational manifold of the molecular gas is well in thermodynamic equilibrium. Further, we demonstrate an accurate, calibration-free determination of the gas temperature from the measured spectroscopic data.

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Section: Introductionmentioning

confidence: 99%

Verifying thermodynamic equilibrium of molecular manifolds: Kennard-Stepanov spectroscopy of a molecular gas

et al. 2017

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“…1 reaches zero. This is attributed to residual heating, as could be due to a small quenching of excited state rubidium atoms in the ultrahigh pressure buffer gas environment 19 . Our data could be explained by an average decrease of the 27 ns natural lifetime of the rubidium 5P-state due to quenching in inelastic collisions by roughly 1 ns at 230 bar argon buffer gas pressure, which would be consistent with the directly measured value of the lifetime change of 0(±2) ns.…”

mentioning

confidence: 99%

Laser cooling by collisional redistribution of radiation

Vogl

Weitz

2009

Nature

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The general idea that optical radiation may cool matter was put forward 80 years ago. Doppler cooling of dilute atomic gases is an extremely successful application of this concept. More recently, anti-Stokes cooling in multilevel systems has been explored, culminating in the optical refrigeration of solids. Collisional redistribution of radiation has been proposed as a different cooling mechanism for atomic two-level systems, although experimental investigations using moderate-density gases have not reached the cooling regime. Here we experimentally demonstrate laser cooling of an atomic gas based on collisional redistribution of radiation, using rubidium atoms in argon buffer gas at a pressure of 230 bar. The frequent collisions in the ultradense gas transiently shift a highly red-detuned laser beam (that is, one detuned to a much lower frequency) into resonance, whereas spontaneous decay occurs close to the unperturbed atomic resonance frequency. During each excitation cycle, kinetic energy of order k(B)T-that is, the thermal energy (k(B), Boltzmann's constant; T, temperature)-is extracted from the dense atomic sample. In a proof-of-principle experiment with a thermally non-isolated sample, we demonstrate relative cooling by 66 K. The cooled gas has a density more than ten orders of magnitude greater than the typical values used in Doppler-cooling experiments, and the cooling power reaches 87 mW. Future applications of the technique may include supercooling beyond the homogeneous nucleation temperature and optical chillers.

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“…Spin destruction collisions do not conserve angular momentum and impose the ultimate limit on the sensitivity of alkali magnetometers. Table 1 summarizes the collisional cross sections relevant to rubidium SERF magnetometers 6,7,8,9,10 . Table 1.…”

Section: Rb-rb Spin Exchange Cross Sectionmentioning

confidence: 99%

Investigations of optical pumping for magnetometry using an auto-locking laser system

Pouliot¹,

Beica

Carew

et al. 2018

Laser Technology for Defense and Security XIV

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We have developed a versatile pulsed laser system for high precision magnetometry. The operating wavelength of the system can be configured to optically pump alkali vapors such as rubidium and cesium. The laser system consists of an auto-locked, interference filter stabilized, external cavity diode laser (ECDL), a tapered waveguide amplifier, and a pulsing module. The auto-locking controller can be used by an untrained operator to stabilize the laser frequency with respect to a library of atomic, molecular, and solid-state spectral markers. The ECDL output can be amplified from 20 mW to 2 W in continuous wave (CW) mode. The pulsing module, which includes an acousto-optic modulator (AOM), can generate pulses with durations of 20 ns and repetition rates of several MHz. Accordingly, the laser system is well suited for applications such as gravimetry, magnetometry, and differential-absorption lidar. In this work, we focus on magnetometric applications and demonstrate that the laser source is suitable for optically pumping rubidium vapor. We also describe numerical simulations of optical pumping relevant to the rubidium D1 and D2 transitions at 795 nm and 780 nm respectively. These studies are relevant to the design and construction of a new generation of portable, rubidium, spinexchange relaxation-free (SERF) magnetometers, capable of sensitivities of 1 fT Hz -1/2 1 .

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Quenching cross sections for alkali-inert gas collisions

Abstract: The cross sections for quenching the lowest n2p states of the alkali atoms Li, Na, K, and Rb by the inert gases He, Ne, Ar, Kr, and Xe are presented for 5 eV Show more

Cited by 33 publications

References 27 publications

Verifying thermodynamic equilibrium of molecular manifolds: Kennard-Stepanov spectroscopy of a molecular gas

Verifying thermodynamic equilibrium of molecular manifolds: Kennard-Stepanov spectroscopy of a molecular gas

Laser cooling by collisional redistribution of radiation

Investigations of optical pumping for magnetometry using an auto-locking laser system

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