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We report the all-optical production of Bose-Einstein condensates (BEC) of 39K atoms. We directly load 3 × 107 atoms in a large volume optical dipole trap from gray molasses on the D1 transition. We then apply a small magnetic quadrupole field to polarize the sample before transferring the atoms in a tightly confining optical trap. Evaporative cooling is finally performed close to a Feshbach resonance to enhance the scattering length. Our setup allows one to cross the BEC threshold with 3 × 105 atoms every 7 s. As an illustration of the interest of the tunability of the interactions we study the expansion of Bose-Einstein condensates in the one-dimensional to three-dimensional crossover. [ABSTRACT FROM AUTHOR]

We report on the production of 39K matter-wave bright solitons, i.e., one-dimensional matter waves that propagate without dispersion thanks to attractive interactions. The volume of the soliton is studied as a function of the scattering length through three-body losses, revealing peak densities as high as ~5×1020m-3. Our solitons, close to the collapse threshold, are strongly bound and will find applications in fundamental physics and atom interferometry. [ABSTRACT FROM AUTHOR]