Anisotropic sub-Doppler laser cooling in dysprosium magneto-optical traps

Youn, Seo Ho; Lu, Mingwu; Lev, Benjamin

doi:10.1103/physreva.82.043403

Cited by 10 publications

(11 citation statements)

References 25 publications

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“…Double structures were previously reported for Rb [30], Dy [21] and Ca [31] MOTs. The specific cloud density profile in the Rb MOT was caused by a bi-harmonical confining potential coming from the sub-Doppler part of a magneto-optical trapping force [30].…”

Section: B the Symmetric Regimesupporting

confidence: 64%

“…For nearly all transitions involved in laser cooling of hollow-shell lanthanides, the magnetic Landé g-factors of the upper and lower cooling levels are close to each other [18,19]. As a result, efficient sub-Doppler cooling was observed directly in the first-stage MOT of Tm [20], Dy [21], Er [22] and Ho [7] even in the presence of a strong magnetic field gradient. However, sub-Doppler cooling in the second-stage MOT has not been reported yet.…”

Section: Introductionmentioning

confidence: 99%

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Two-temperature momentum distribution in a thulium magneto-optical trap

et al. 2017

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Second-stage laser cooling of thulium atoms at the 530.7 nm transition with a natural linewidth of 350 kHz offers an interesting possibility to study different regimes of a magneto-optical trap (MOT). The intermediate value of the spectral linewidth of the cooling transition allows the observation of three distinct regimes depending on the intensity and detuning of the cooling beams, namely, the "bowl-shaped" regime when light pressure force competes with gravity, the "double structure" regime with interplay between the Doppler and polarization-gradient (sub-Doppler) cooling, and the "symmetric" regime when Doppler cooling dominates over sub-Doppler cooling and gravity. The polarization-gradient cooling manifests itself by a two-temperature momentum distribution of atoms resulting in a double-structure of the spatial MOT profile consisting of a cold central fraction surrounded by a hot halo. We studied the double structure regime at different saturation parameters and compared observations with calculations based on semiclassical and quantum approaches. The quantum treatment adequately reproduces experimental results if the MOT magnetic field is properly taken into account.

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Section: B the Symmetric Regimesupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Two-temperature momentum distribution in a thulium magneto-optical trap

et al. 2017

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“…However, this combination requires the use of a narrow-linewidth dye-based laser to obtain 626-nm light. We note that the large Landé g factor difference between the excited state (1.29) and ground state (1.24) suggests that intra-MOT sub-Doppler cooling [23,30] will not be as effective on this transition.…”

Section: Alternative Laser-cooling Transitionsmentioning

confidence: 89%

“…Quantitative understanding of the population, dynamics, and cooling mechanisms [23] of the Dy MOT requires accurate knowledge of the 421-nm transition's linewidth. To ensure the use of the correct value of the 421-nm transition linewidth in laser-cooling calculations, we remeasured this linewidth using the crossed-beam method described earlier, though with a 421-nm beam derived from a frequency-doubled Ti:sapphire laser.…”

Section: The 421-nm Transitionmentioning

confidence: 99%

Spectroscopy of a narrow-line laser-cooling transition in atomic dysprosium

Youn

Lev

2011

Phys. Rev. A

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The laser cooling and trapping of ultracold neutral dysprosium has been demonstrated recently using the broad, open, 421-nm cycling transition. Narrow-line magneto-optical trapping of Dy on longer wavelength transitions would enable the preparation of ultracold Dy samples suitable for loading optical dipole traps and subsequent evaporative cooling. We have identified the closed 741-nm cycling transition as a candidate for the narrow-line cooling of Dy. We present experimental data on the isotope shifts, the hyperfine constants A and B, and the decay rate of the 741-nm transition. In addition, we report a measurement of the 421-nm transition's linewidth, which agrees with previous measurements. We summarize the laser-cooling characteristics of these transitions as well as other narrow cycling transitions that may prove useful for cooling Dy.

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“…Later on, lanthanides started to draw much attention: Ultracold erbium atoms were produced in a magneto-optical trap [15,16]. More recently Bose-Einstein condensation was reached with erbium [17,18] and dysprosium [19][20][21][22][23] and noncondensed ultracold gases of thulium [24,25] and holmium [26] were also produced. These achievements stimulated both theoretical [27][28][29][30][31] and experimental studies [32][33][34], which complemented the work * maxence.lepers@u-psud.fr on ytterbium, the heavier (closed-shell) lanthanide element (see, for example, [35] and references therein).…”

Section: Introductionmentioning

confidence: 99%

Anisotropic optical trapping of ultracold erbium atoms

Lepers¹,

Wyart²,

Dulieu³

2014

Phys. Rev. A

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Ultracold atoms confined in a dipole trap are submitted to a potential whose depth is proportional to the real part of their dynamic dipole polarizability. The atoms also experience photon scattering whose rate is proportional to the imaginary part of their dynamic dipole polarizability. In this article we calculate the complex dynamic dipole polarizability of ground-state erbium, a rare-earth atom that was recently Bose-condensed. The polarizability is calculated with the sum-over-state formula inherent to second-order perturbation theory. The summation is performed on transition energies and transition dipole moments from ground-state erbium, which are computed using the Racah-Slater least-square fitting procedure provided by the Cowan codes. This allows us to predict 9 unobserved odd-parity energy levels of total angular momentum J=5, 6 and 7, in the range 25000-31000 cm-1 above the ground state. Regarding the trapping potential, we find that ground-state erbium essentially behaves like a spherically-symmetric atom, in spite of its large electronic angular momentum. We also find a mostly isotropic van der Waals interaction between two ground-state erbium atoms, characterized by a coefficient C_6^{iso}=1760 a.u.. On the contrary, the photon-scattering rate shows a pronounced anisotropy, since it strongly depends on the polarization of the trapping light.Comment: 15 pages, 5 figure

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Anisotropic sub-Doppler laser cooling in dysprosium magneto-optical traps

Cited by 10 publications

References 25 publications

Two-temperature momentum distribution in a thulium magneto-optical trap

Two-temperature momentum distribution in a thulium magneto-optical trap

Spectroscopy of a narrow-line laser-cooling transition in atomic dysprosium

Anisotropic optical trapping of ultracold erbium atoms

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