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

We report on the production of a K-41-Rb-87 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 Rb-87 first by magnetic and then by optical evaporation, while K-41 is sympathetically cooled by elastic collisions with Rb-87. We eventually produce two-component condensates with more than 10(5) 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.