Dual-species Bose-Einstein condensate of K 41 and Rb 87 in a hybrid trap

We report on the production of a K41-Rb87 dual-species Bose-Einstein condensate in a hybrid trap, consisting of a magnetic quadrupole and an optical dipole potential. After loading both atomic species in the trap, we cool down Rb87 first by magnetic and then by optical evaporation, while K41 is sympathetically cooled by elastic collisions with Rb87. We eventually produce two-component condensates with more than 105 atoms and tunable species population imbalance. We observe the immiscibility of the quantum mixture by measuring the density profile of each species after releasing them from the trap.