In this work, a broadband 1071 nm crossed optical dipole trap was loaded simultaneously from a two-atomic-species K-Rb magneto-optical trap. The number of atoms loaded into the dipole trap, for both species, was characterized as a function of different laser parameters and loading procedures. The best observed loading procedure for K is explained by the ac Stark shift of the hyperfine states involved in the ${D}_{2}$ transition. For the optimum conditions, the dipole trap has about $3\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${}^{39}$ K atoms at an atomic density of $7\ifmmode\times\else\texttimes\fi{}{10}^{12}$ cm${}^{\ensuremath{-}3}$ and $2\ifmmode\times\else\texttimes\fi{}{10}^{6}$ Rb atoms at an atomic density of $5\ifmmode\times\else\texttimes\fi{}{10}^{12}$ cm${}^{\ensuremath{-}3}$, with temperatures of 22 and 10 $\ensuremath{\mu}$K, respectively. Finally, by studying the time evolution of both species trapped in the crossed optical dipole trap, we have observed a nonexponential decay associated with heteronuclear two-body losses. Such losses may be due to KRb photoassociation by the broadband 1071 nm laser.In this work, a broadband 1071 nm crossed optical dipole trap was loaded simultaneously from a two-atomic-species K-Rb magneto-optical trap. The number of atoms loaded into the dipole trap, for both species, was characterized as a function of different laser parameters and loading procedures. The best observed loading procedure for K is explained by the ac Stark shift of the hyperfine states involved in the ${D}_{2}$ transition. For the optimum conditions, the dipole trap has about $3\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${}^{39}$K atoms at an atomic density of $7\ifmmode\times\else\texttimes\fi{}{10}^{12}$ cm${}^{\ensuremath{-}3}$ and $2\ifmmode\times\else\texttimes\fi{}{10}^{6}$ Rb atoms at an atomic density of $5\ifmmode\times\else\texttimes\fi{}{10}^{12}$ cm${}^{\ensuremath{-}3}$, with temperatures of 22 and 10 $\ensuremath{\mu}$K, respectively. Finally, by studying the time evolution of both species trapped in the crossed optical dipole trap, we have observed a nonexponential decay associated with heteronuclear two-body losses. Such losses may be due to KRb photoassociation by the broadband 1071 nm laser.

Physical Review AAug 9, 20134 citations

Trap loss in a rubidium crossed dipole trap by short-range photoassociation

Carlos Renato Menegatti, Bruno Marangoni, Nadia Bouloufa-Maafa +2 more

Significant two-body losses are observed in an ultracold gas of ${}^{85}$ Rb or ${}^{87}$ Rb atoms in a crossed dipole trap implemented with a broadband laser with a wavelength around 1071 nm. Using available spectroscopic data on the excited states of Rb ${}_{2}$ , as well as accurate computed transition dipole moment functions, we interpret these losses as due to photoassociation of deeply bound levels of the 0 ${}_{u}^{+}$ coupled states by the trapping laser, followed by spontaneous emission down to bound levels of the Rb ${}_{2}$ ground state thus forming ultracold molecules. The observed ratio of 3.3 between the loss rates of ${}^{87}$ Rb and ${}^{85}$ Rb is well reproduced by the theoretical model.Significant two-body losses are observed in an ultracold gas of ${}^{85}$Rb or ${}^{87}$Rb atoms in a crossed dipole trap implemented with a broadband laser with a wavelength around 1071 nm. Using available spectroscopic data on the excited states of Rb${}_{2}$, as well as accurate computed transition dipole moment functions, we interpret these losses as due to photoassociation of deeply bound levels of the 0${}_{u}^{+}$ coupled states by the trapping laser, followed by spontaneous emission down to bound levels of the Rb${}_{2}$ ground state thus forming ultracold molecules. The observed ratio of 3.3 between the loss rates of ${}^{87}$Rb and ${}^{85}$Rb is well reproduced by the theoretical model.

Physical Review AMay 8, 201324 citations

Trapping of Single Atoms in an Off-Resonance Optical Dipole Trap

WORLD SCIENTIFIC eBooksDec 1, 20060 citations

{D}_{2}

transition. For the optimum conditions, the dipole trap has about $3\ifmmode\times\else\texttimes\fi{}{10}^{6}$

{}^{39}

K atoms at an atomic density of $7\ifmmode\times\else\texttimes\fi{}{10}^{12}$ cm${}^{\ensuremath{-}3}$ and $2\ifmmode\times\else\texttimes\fi{}{10}^{6}$ Rb atoms at an atomic density of $5\ifmmode\times\else\texttimes\fi{}{10}^{12}$ cm${}^{\ensuremath{-}3}$, with temperatures of 22 and 10 $\ensuremath{\mu}$K, respectively. Finally, by studying the time evolution of both species trapped in the crossed optical dipole trap, we have observed a nonexponential decay associated with heteronuclear two-body losses. Such losses may be due to KRb photoassociation by the broadband 1071 nm laser.

Significant two-body losses are observed in an ultracold gas of

{}^{85}

Rb or

{}^{87}

Rb atoms in a crossed dipole trap implemented with a broadband laser with a wavelength around 1071 nm. Using available spectroscopic data on the excited states of Rb

{}_{2}

, as well as accurate computed transition dipole moment functions, we interpret these losses as due to photoassociation of deeply bound levels of the 0

{}_{u}^{+}

coupled states by the trapping laser, followed by spontaneous emission down to bound levels of the Rb

{}_{2}

ground state thus forming ultracold molecules. The observed ratio of 3.3 between the loss rates of

{}^{87}

Rb and

{}^{85}

Rb is well reproduced by the theoretical model.