Laser assisted collisions at ultracold temperatures

José Paulo D'Incao, Chris H. Greene

Adrien Devolder, Eliane Luc-Koenig, Osman Atabek +2 more

Synopsis We propose a new kind of Feshbach Resonance (FR) : the Laser-Assisted Self-Induced Feshbach Resonance (LASIFR), applicable for all mixtures of ultracold atoms. The interspecies scattering length characterizing elastic collisions, a key property for many applications of ultracold quantum gases, can be controlled by a LASIFR through the laser intensity and the frequency. It can be also used for the formation of ultracold polar molecules.

Paul D. Lett, Poul Jessen, William D. Phillips +3 more

Gensemer, Sanchez-Villicana, Ciris +1 more

I. S. Cojocaru, Sergey Pyatchenkov, Stepan Snigirev +12 more

We studied light-assisted collisions of Tm atoms in a magneto-optical trap (MOT), working on a weak cooling transition at 530.7 nm [$4{f}^{13}(^{2}F^{o})6{s}^{2},\phantom{\rule{0.16em}{0ex}}J=7/2,\phantom{\rule{0.16em}{0ex}}F=4$ to $4{f}^{12}(^{3}H_{6})5{d}_{5/2}6{s}^{2},\phantom{\rule{0.16em}{0ex}}J=9/2,\phantom{\rule{0.16em}{0ex}}F=5$]. We observed a strong influence from radiation trapping and light-assisted collisions on the dynamics of this trap. We carefully separated these two contributions and measured the binary loss rate constant at different laser powers and detuning frequencies near the cooling transition. Analyzing losses from the MOT, we found the light-assisted inelastic binary loss rate constant to reach values of up to $\ensuremath{\beta}={10}^{\ensuremath{-}9}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{3}/\mathrm{s}$ and gave the upper bound on a branching ratio $k<0.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ for the 530.7 nm transition.

S. D. Gensemer, V. Sánchez-Villicaña, S. Ciris +1 more