Experiments in a two species MOT

We trap and cool a gas composed of ${}^{40}\mathrm{K}$ and ${}^{87}\mathrm{Rb},$ using a two-species magneto-optical trap (MOT). This trap represents the first step towards cooling the Bose-Fermi mixture to quantum degeneracy. Laser light for the MOT is derived from laser diodes and amplified with a single high-power semiconductor amplifier chip. The four-color laser system is described, and the single-species and two-species MOTs are characterized. Atom numbers of $1\ifmmode\times\else\texttimes\fi{}{10}^{7}$ ${}^{40}\mathrm{K}$ and $2\ifmmode\times\else\texttimes\fi{}{10}^{9}$ ${}^{87}\mathrm{Rb}$ are trapped in the two-species MOT. Observation of trap loss due to collisions between species is presented and future prospects for the experiment are discussed.We trap and cool a gas composed of ${}^{40}\mathrm{K}$ and ${}^{87}\mathrm{Rb},$ using a two-species magneto-optical trap (MOT). This trap represents the first step towards cooling the Bose-Fermi mixture to quantum degeneracy. Laser light for the MOT is derived from laser diodes and amplified with a single high-power semiconductor amplifier chip. The four-color laser system is described, and the single-species and two-species MOTs are characterized. Atom numbers of $1\ifmmode\times\else\texttimes\fi{}{10}^{7}$ ${}^{40}\mathrm{K}$ and $2\ifmmode\times\else\texttimes\fi{}{10}^{9}$ ${}^{87}\mathrm{Rb}$ are trapped in the two-species MOT. Observation of trap loss due to collisions between species is presented and future prospects for the experiment are discussed.

arXiv:cond-mat/0108287Physical Review AJan 3, 200284 citations

Experiments and theory

Jerry B. Marion, J. L. Fowler

Interscience Publishers eBooksJan 1, 196364 citations

Diffractive chips for magneto-optical trapping of two atomic species

Zhaoning Yu, Garrett Hickman, Mark E. Saffman +1 more

Grating-based structures have recently been used as components of magneto-optical traps (MOT) to simplify the setup for trapping Rb atoms. Here, we design diffractive chips to trap more than one atom species. Our full-wave simulations show that a two-dimensional (2D) grating chip can simultaneously have high force-balancing efficiency for a wavelength of 780 nm for trapping Rb atoms and a wavelength of 852 nm for Cs atoms. We fabricated and characterized a mm-scale grating chip using electron-beam lithography, and are in the process of trapping experiments. Our work opens the door to compact multi-species MOTs.Grating-based structures have recently been used as components of magneto-optical traps (MOT) to simplify the setup for trapping Rb atoms. Here, we design diffractive chips to trap more than one atom species. Our full-wave simulations show that a two-dimensional (2D) grating chip can simultaneously have high force-balancing efficiency for a wavelength of 780 nm for trapping Rb atoms and a wavelength of 852 nm for Cs atoms. We fabricated and characterized a mm-scale grating chip using electron-beam lithography, and are in the process of trapping experiments. Our work opens the door to compact multi-species MOTs.

Quantum Nanophotonic Materials, Devices, and SystemsAug 20, 20200 citations

Theory Meets Experiment

R. Casalbuoni, G. Domokos, Susan Kovesi-Domokos +1 more

Jun 1, 19950 citations

Two-color laser cooling for K40−Rb87 quantum gas mixtures

Yann Kiefer, Max Hachmann, Andreas Hemmerich

We present an efficient cooling scheme for fermionic $^{40}\mathrm{K}$ atoms, using laser light red and blue detuned with respect to the D2 and D1 principle fluorescence lines, respectively. The cooling scheme is found to significantly increase the saturation level for loading of a $^{40}\mathrm{K}$ magneto-optical trap (MOT), resulting in increased atom numbers or decreased cycle times. While the attainable $^{40}\mathrm{K}$ atom number is approximately doubled if exclusively $^{40}\mathrm{K}$ atoms are cooled, the scheme is particularly powerful for dual-species MOTs, for example, if $^{40}\mathrm{K}$ and $^{87}\mathrm{Rb}$ atoms are cooled simultaneously in the same MOT configuration. The typical atom losses due to light-assisted heteronuclear collisions between $^{40}\mathrm{K}$ and $^{87}\mathrm{Rb}$ seem to be reduced, giving rise to a threefold improvement of the $^{40}\mathrm{K}$ atom number as compared to that in a conventional dual-species MOT, operating merely with D2 light. Our scheme can be a useful extension to most dual-species experiments, aiming to reach simultaneous degeneracy of both species.We present an efficient cooling scheme for fermionic $^{40}\mathrm{K}$ atoms, using laser light red and blue detuned with respect to the D2 and D1 principle fluorescence lines, respectively. The cooling scheme is found to significantly increase the saturation level for loading of a $^{40}\mathrm{K}$ magneto-optical trap (MOT), resulting in increased atom numbers or decreased cycle times. While the attainable $^{40}\mathrm{K}$ atom number is approximately doubled if exclusively $^{40}\mathrm{K}$ atoms are cooled, the scheme is particularly powerful for dual-species MOTs, for example, if $^{40}\mathrm{K}$ and $^{87}\mathrm{Rb}$ atoms are cooled simultaneously in the same MOT configuration. The typical atom losses due to light-assisted heteronuclear collisions between $^{40}\mathrm{K}$ and $^{87}\mathrm{Rb}$ seem to be reduced, giving rise to a threefold improvement of the $^{40}\mathrm{K}$ atom number as compared to that in a conventional dual-species MOT, operating merely with D2 light. Our scheme can be a useful extension to most dual-species experiments, aiming to reach simultaneous degeneracy of both species.

Physical Review AFeb 14, 20240 citations

We trap and cool a gas composed of

{}^{40}\mathrm{K}

and

{}^{87}\mathrm{Rb},

using a two-species magneto-optical trap (MOT). This trap represents the first step towards cooling the Bose-Fermi mixture to quantum degeneracy. Laser light for the MOT is derived from laser diodes and amplified with a single high-power semiconductor amplifier chip. The four-color laser system is described, and the single-species and two-species MOTs are characterized. Atom numbers of $1\ifmmode\times\else\texttimes\fi{}{10}^{7}$

{}^{40}\mathrm{K}

and $2\ifmmode\times\else\texttimes\fi{}{10}^{9}$

{}^{87}\mathrm{Rb}

are trapped in the two-species MOT. Observation of trap loss due to collisions between species is presented and future prospects for the experiment are discussed.

We present an efficient cooling scheme for fermionic

^{40}\mathrm{K}

atoms, using laser light red and blue detuned with respect to the D2 and D1 principle fluorescence lines, respectively. The cooling scheme is found to significantly increase the saturation level for loading of a

^{40}\mathrm{K}

magneto-optical trap (MOT), resulting in increased atom numbers or decreased cycle times. While the attainable

^{40}\mathrm{K}

atom number is approximately doubled if exclusively

^{40}\mathrm{K}

atoms are cooled, the scheme is particularly powerful for dual-species MOTs, for example, if

^{40}\mathrm{K}

and

^{87}\mathrm{Rb}

atoms are cooled simultaneously in the same MOT configuration. The typical atom losses due to light-assisted heteronuclear collisions between

^{40}\mathrm{K}

and

^{87}\mathrm{Rb}

seem to be reduced, giving rise to a threefold improvement of the

^{40}\mathrm{K}

atom number as compared to that in a conventional dual-species MOT, operating merely with D2 light. Our scheme can be a useful extension to most dual-species experiments, aiming to reach simultaneous degeneracy of both species.