We present an efficient scheme to implement a gray optical molasses for sub-Doppler cooling of $^{6}\mathrm{Li}$ atoms with minimum experimental overhead. To integrate the ${D}_{1}$ light for the gray molasses cooling into the same optical setup that is used for the ${D}_{2}$ light for a standard magneto-optical trap (MOT), we rapidly switch the injection seeding of a slave laser between the ${D}_{2}$ and the ${D}_{1}$ light sources. Switching times as short as 30 $\ensuremath{\mu}\mathrm{s}$ can be achieved, inferred from monitor optical beat signals. The resulting low-intensity molasses cools a sample of $N=9\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms to about 60 $\ensuremath{\mu}\mathrm{K}$. A maximum phase-space density of $\ensuremath{\rho}=1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ is observed. On the same setup, the performance of the GM is compared to that of narrow-line cooling in an ultraviolet (UV) MOT, following the procedure in Sebastian et al. [J. Sebastian, Ch. Gross, K. Li, H. C. J. Gan, W. Li, and K. Dieckmann, Phys. Rev. A 90, 033417 (2014)]. Further, we compare the production of a degenerate Fermi gas using both methods. Loading an optical dipole trap from the gray molasses yields a quantum degenerate sample with $3.3\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms, while loading from the denser UV MOT yields $2.4\ifmmode\times\else\texttimes\fi{}{10}^{6}$ atoms. Where the highest atom numbers are not a priority this implementation of the gray molasses technique yields sufficiently large samples for a comparatively low technical effort.We present an efficient scheme to implement a gray optical molasses for sub-Doppler cooling of $^{6}\mathrm{Li}$ atoms with minimum experimental overhead. To integrate the ${D}_{1}$ light for the gray molasses cooling into the same optical setup that is used for the ${D}_{2}$ light for a standard magneto-optical trap (MOT), we rapidly switch the injection seeding of a slave laser between the ${D}_{2}$ and the ${D}_{1}$ light sources. Switching times as short as 30 $\ensuremath{\mu}\mathrm{s}$ can be achieved, inferred from monitor optical beat signals. The resulting low-intensity molasses cools a sample of $N=9\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms to about 60 $\ensuremath{\mu}\mathrm{K}$. A maximum phase-space density of $\ensuremath{\rho}=1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ is observed. On the same setup, the performance of the GM is compared to that of narrow-line cooling in an ultraviolet (UV) MOT, following the procedure in Sebastian et al. [J. Sebastian, Ch. Gross, K. Li, H. C. J. Gan, W. Li, and K. Dieckmann, Phys. Rev. A 90, 033417 (2014)]. Further, we compare the production of a degenerate Fermi gas using both methods. Loading an optical dipole trap from the gray molasses yields a quantum degenerate sample with $3.3\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms, while loading from the denser UV MOT yields $2.4\ifmmode\times\else\texttimes\fi{}{10}^{6}$ atoms. Where the highest atom numbers are not a priority this implementation of the gray molasses technique yields sufficiently large samples for a comparatively low technical effort.

arXiv:1808.06836Physical Review AAug 24, 201810 citations

Realization of large 7 Li Bose-Einstein condensates using gray molasses

Kyungtae Kim, SeungJung Huh, Kiryang Kwon +1 more

Bulletin of the American Physical SocietyMay 28, 20190 citations

Sub-Doppler laser cooling of40K with Raman gray molasses on the ${D}_{2}$ lineSub-Doppler laser cooling of40K with Raman gray molasses on the ${D}_{2}$ line

G D Bruce, E Haller, Bruno Peaudecerf +6 more

Gray molasses is a powerful tool for sub-Doppler laser cooling of atoms to low temperatures. For alkaline atoms, this technique is commonly implemented with cooling lasers which are blue-detuned from either the D 1 or D 2 line. Here we show that efficient gray molasses can be implemented on the D 2 line of 40 K with red -detuned lasers. We obtained temperatures of , which enables direct loading of atoms from a magneto-optical trap into an optical dipole trap. We support our findings by a one-dimensional model and three-dimensional numerical simulations of the optical Bloch equations which qualitatively reproduce the experimentally observed cooling effects.Gray molasses is a powerful tool for sub-Doppler laser cooling of atoms to low temperatures. For alkaline atoms, this technique is commonly implemented with cooling lasers which are blue-detuned from either the D 1 or D 2 line. Here we show that efficient gray molasses can be implemented on the D 2 line of 40 K with red -detuned lasers. We obtained temperatures of , which enables direct loading of atoms from a magneto-optical trap into an optical dipole trap. We support our findings by a one-dimensional model and three-dimensional numerical simulations of the optical Bloch equations which qualitatively reproduce the experimentally observed cooling effects.

arXiv:1612.04583Journal of Physics B Atomic Molecular and Optical PhysicsApr 12, 201724 citations

Optical molasses and tests of a new theory of laser cooling

David S. Weiss, P. J. Ungar, Yaakov Shevy +2 more

Quantum Electronics and Laser Science ConferenceDec 1, 19890 citations

We present an efficient scheme to implement a gray optical molasses for sub-Doppler cooling of

^{6}\mathrm{Li}

atoms with minimum experimental overhead. To integrate the

{D}_{1}

light for the gray molasses cooling into the same optical setup that is used for the

{D}_{2}

light for a standard magneto-optical trap (MOT), we rapidly switch the injection seeding of a slave laser between the

{D}_{2}

and the

{D}_{1}

light sources. Switching times as short as 30 $\ensuremath{\mu}\mathrm{s}$ can be achieved, inferred from monitor optical beat signals. The resulting low-intensity molasses cools a sample of $N=9\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms to about 60 $\ensuremath{\mu}\mathrm{K}$. A maximum phase-space density of $\ensuremath{\rho}=1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ is observed. On the same setup, the performance of the GM is compared to that of narrow-line cooling in an ultraviolet (UV) MOT, following the procedure in Sebastian et al. [J. Sebastian, Ch. Gross, K. Li, H. C. J. Gan, W. Li, and K. Dieckmann, Phys. Rev. A 90, 033417 (2014)]. Further, we compare the production of a degenerate Fermi gas using both methods. Loading an optical dipole trap from the gray molasses yields a quantum degenerate sample with $3.3\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms, while loading from the denser UV MOT yields $2.4\ifmmode\times\else\texttimes\fi{}{10}^{6}$ atoms. Where the highest atom numbers are not a priority this implementation of the gray molasses technique yields sufficiently large samples for a comparatively low technical effort.

Sub-Doppler laser cooling of40K with Raman gray molasses on the

{D}_{2}

line