Cooling and trapping of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Rb</mml:mi><mml:mprescripts /><mml:none /><mml:mn>85</mml:mn></mml:mmultiscripts></mml:math>atoms in the ground hyperfine<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>F</mml:mi><mml:mo>=</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:math>state

Tiwari, V. B.; Singh, Sunita; Rawat, H. S.; Mehendale, S. C.

doi:10.1103/physreva.78.063421

Cited by 22 publications

(29 citation statements)

References 17 publications

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“…The trapping scheme used in this MOT provides tighter confinement than could be achieved with our original configuration, with spring constants comparable to those reported in atomic type-II MOTs [20] (though still one to two orders of magnitude less than those in typical type-I atomic MOTs [32]). We note that a MOT was observed in [15] when driving confining transitions from the | = = 〉 J F 3 2, 2 and | = = 〉 J F 1 2, 1 manifolds (but anti-confining transitions from the | = = 〉 J F 3 2, 1 and | = = 〉 J F 1 2, 0 manifolds), but not when the MOT polarizations or magnetic field gradient were reversed.…”

Section: Resultsmentioning

confidence: 52%

Improved magneto–optical trapping of a diatomic molecule

et al. 2015

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We present experimental results from a new scheme for magnetooptically trapping strontium monofluoride (SrF) molecules, which provides increased confinement compared to our original work. The improved trap employs a new approach to magneto-optical trapping presented by M. Tarbutt, arXiv preprint 1409.0244, which provided insight for the first time into the source of the restoring force in magneto-optical traps (MOTs) where the cycling transition includes dark Zeeman sublevels (known as type-II MOTs). We measure a radial spring constant 20× greater than in our original work with SrF, comparable to the spring constants reported in atomic type-II MOTs. We achieve a trap lifetime τ MOT = 136(2) ms, over 2× longer than originally reported for SrF. Finally, we demonstrate further cooling of the trapped molecules by briefly increasing the trapping lasers' detunings. Our trapping scheme remains a straightforward extension of atomic techniques and marks a step towards the direct production of large, dense, ultracold molecular gases via laser cooling.

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Section: Resultsmentioning

confidence: 52%

Improved magneto–optical trapping of a diatomic molecule

et al. 2015

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“…Type-II MOTs like this one (operating from F″ to F′ = F″ − 1) tend to be weaker and larger than their type-I counterparts (operating from F″ to F′ = F″+1 ), with sizes on the order of 1 mm [43]. Typically type-II MOTs do not reach the Doppler limit [23,44]. By analogy with SrF, which has similar molecular parameters to YO, we anticipate the final temperature of the orange MOT to be on the order of 1 mK, larger than the Doppler temperature T D = 110 μK.…”

Section: First Stage Laser Coolingmentioning

confidence: 99%

Prospects for a narrow line MOT in YO

et al. 2015

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In addition to being suitable for laser cooling and trapping in a magneto-optical trap (MOT) using a relatively broad ∼ ( 5 MHz) transition, the molecule YO possesses a narrow-line transition. This forbidden transition between the Σ X 2 and Δ ′ A 2 3 2 states has linewidth π ∼ × 2 160 kHz. After cooling in a MOT on the 614 nm Σ X 2 to Π A 2 1 2 (orange) transition, the narrow 690 nm (red) transition can be used to further cool the sample, requiring only minimal additions to the first stage system. We estimate that the narrow line cooling stage will bring the temperature from ∼1 mK to ∼10 μK, significantly advancing the frontier on direct cooling achievable for molecules.

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“…In this case, atoms can be optically pumped into a dark state and uncouple from the light, and so these dark states must be destabilized [18] if the cooling is to be effective. Type-II MOTs have been studied experimentally [2,[19][20][21][22][23][24]. Compared to type-I MOTs, they tend to have higher temperatures, typically in the 2-20 mK range, larger cloud sizes, typically a few millimetres, and lower densities.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional Doppler, polarization-gradient, and magneto-optical forces for atoms and molecules with dark states

Devlin

Tarbutt

2016

New J. Phys.

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We theoretically investigate the damping and trapping forces in a three-dimensional magneto-optical trap (MOT), by numerically solving the optical Bloch equations. We focus on the case where there are dark states because the atom is driven on a 'type-II' system where the angular momentum of the excited state, F¢, is less than or equal to that of the ground state, F. For these systems we find that the force in a three-dimensional light field has very different behaviour to its one dimensional counterpart. This differs from the more commonly used 'type-I' systems (F F 1 ¢ = + ) where the 1D and 3D behaviours are similar. Unlike type-I systems where, for red-detuned light, both Doppler and sub-Doppler forces damp the atomic motion towards zero velocity, in type-II systems in 3D, the Doppler force and polarization gradient force have opposite signs. As a result, the atom is driven towards a non-zero equilibrium velocity, v 0 , where the two forces cancel. We find that v 0 2 scales linearly with the intensity of the light and is fairly insensitive to the detuning from resonance. We also discover a new magneto-optical force that alters the normal MOT force at low magnetic fields and whose influence is greatest in the type-II systems. We discuss the implications of these findings for the laser cooling and magneto-optical trapping of molecules where type-II transitions are unavoidable in realising closed optical cycling transitions.

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Cooling and trapping ofRb85atoms in the ground hyperfineF=2state

Cited by 22 publications

References 17 publications

Improved magneto–optical trapping of a diatomic molecule

Improved magneto–optical trapping of a diatomic molecule

Prospects for a narrow line MOT in YO

Three-dimensional Doppler, polarization-gradient, and magneto-optical forces for atoms and molecules with dark states

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