Bichromatic Slowing and Collimation to Make an Intense Helium Beam

Partlow, M.; Miao, X.; Bochmann, J.; Cashen, M.; Metcalf, Harold

doi:10.1103/physrevlett.93.213004

Cited by 50 publications

(52 citation statements)

References 19 publications

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“…After the slowing section, the mean velocity of the atoms is reduced to a few tens of m/s (Morita and Kumakura, 1991). An alternative slowing (and collimation) technique for He* was proposed and demonstrated in the group of Metcalf Metcalf, 2003, 2001;Partlow et al, 2004). Applying a bichromatic force at high power around 1083 nm a record-high capture angle from the discharge source of ∼0.18 radians was demonstrated over the unprecedentedly small distance of 5 cm, albeit with considerable losses.…”

Section: B Intense and Slow Beams Of Metastable Atomsmentioning

confidence: 99%

“…This is achieved by transverse collimation of the beam of metastable atoms using two-dimensional (2D) transverse radiative pressure forces (Aspect et al, 1990;Hoogerland et al, 1996b;Metcalf and van der Straten, 1999;Morita and Kumakura, 1991;Partlow et al, 2004;Rasel et al, 1999;Rooijakkers et al, 1996;Shimizu et al, 1987Shimizu et al, , 1990Vansteenkiste et al, 1991), focussing in a hexapole (Woestenenk et al, 2001) or 2D magneto-optical compression (Labeyrie et al, 1999;Schiffer et al, 1997;Scholz et al, 1994). For maximum efficiency, the collimation zone, which has a typical length of several to a few tens of cm, has to be implemented as close as possible to the source, typically directly after the skimmer.…”

Section: B Intense and Slow Beams Of Metastable Atomsmentioning

confidence: 99%

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Cold and trapped metastable noble gases

et al. 2012

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We review experimental work on cold, trapped metastable noble gases. We emphasize the aspects which distinguish work with these atoms from the large body of work on cold, trapped atoms in general. These aspects include detection techniques and collision processes unique to metastable atoms. We describe several experiments exploiting these unique features in fields including atom optics and statistical physics. We also discuss precision measurements on these atoms including fine structure splittings, isotope shifts, and atomic lifetimes.

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Section: B Intense and Slow Beams Of Metastable Atomsmentioning

confidence: 99%

Section: B Intense and Slow Beams Of Metastable Atomsmentioning

confidence: 99%

Cold and trapped metastable noble gases

et al. 2012

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“…7, the optimum repumping Rabi frequency was found to very closely fit a set of curves proportional to √ δΓ, and this scaling is expected to be generally applicable. Using a least-squares fit, the optimal frequency was determined to be Ω opt ed = 0.536 (14) √ δΓ.…”

Section: Repumpingmentioning

confidence: 99%

“…The bichromatic force in two-level systems has successfully been demonstrated in several atoms and is amply described in prior publications [9][10][11][12][13][14][15][16][17][18]. In brief, the BCF is the coherent force produced by a balanced counterpropagating pair of two-color cw laser beams.…”

Section: Introductionmentioning

confidence: 99%

Simulations of the bichromatic force in multilevel systems

2016

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Coherent optical bichromatic forces have been shown to be effective tools for rapidly slowing and cooling simple atomic systems. While previous estimates suggest that these forces may also be effective for rapidly decelerating molecules or complex atoms, a quantitative treatment for multilevel systems has been lacking. We describe detailed numerical modeling of bichromatic forces by direct numerical solution for the time-dependent density matrix in the rotating-wave approximation. We describe both the general phenomenology of an arbitrary few-level system and the specific requirements for slowing and cooling on a many-level transition in calcium monofluoride (CaF), one of the molecules of greatest current experimental interest. We show that it should be possible to decelerate a cryogenic buffer-gas-cooled beam of CaF nearly to rest without a repumping laser and within a longitudinal distance of about 1 cm. We also compare a full 16-level simulation for the CaF B ↔ X system with a simplified numerical model and with a semiquantitative estimate based on 2-level systems. The simplified model performs nearly as well as the complete version, whereas the 2-level model is useful for making order-of-magnitude estimates, but nothing more.

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“…II below. Further work by Metcalf expanded on this idea by using bichromatic forces to focus and decelerate an atomic beam of metastable helium (He*) [3][4][5]. More recently, our group has designed and evaluated two schemes for longitudinal slowing of a beam of metastable helium by several hundred m/s [6,7].…”

Section: Introductionmentioning

confidence: 99%

Four-color stimulated optical forces for atomic and molecular slowing

2013

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Stimulated optical forces offer a simple and efficient method for providing optical forces far in excess of the saturated radiative force. The bichromatic force, using a counterpropagating pair of two-color beams, has so far been the most effective of these stimulated forces for deflecting and slowing atomic beams. We have numerically studied the evolution of a two-level system under several different bichromatic and polychromatic light fields, while retaining the overall geometry of the bichromatic force. New insights are gained by studying the time-dependent trajectory of the Bloch vector, including a better understanding of the remarkable robustness of bi-and polychromatic forces with imbalanced beam intensities. We show that a four-color polychromatic force exhibits great promise. By adding new frequency components at the third harmonic of the original bichromatic detuning, the force is increased by nearly 50% and its velocity range is extended by a factor of three, while the required laser power is increased by only 33%. The excited-state fraction, crucial to possible application to molecules, is reduced from 41% to 24%. We also discuss some important differences between polychromatic forces and pulse trains from a high-repetition-rate laser.

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Bichromatic Slowing and Collimation to Make an Intense Helium Beam

Cited by 50 publications

References 19 publications

Cold and trapped metastable noble gases

Cold and trapped metastable noble gases

Simulations of the bichromatic force in multilevel systems

Four-color stimulated optical forces for atomic and molecular slowing

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