Abstract
This thesis studies the formation of rubidium molecules by photoassociation (PA) method and develops a method for detecting the formed ground state molecules using collisions of atoms and molecules in an optical dipole trap. In the magneto-optical trap of 85Rb, ultracold rubidium molecules, in the excited-electronic state, were produced using the photoassociation process. With the help of resonance coupling effect, the number of molecules in the ground-electronic state which decay spontaneously from the excited molecular state can be enhanced. The formed ground state molecules and the remaining atoms in the trap were simultaneously loaded into a crossed optical dipole trap. Addition to the background collision losses, the extra losses of 85Rb atoms due to the photoassociated molecules in the optical trap can then be used to estimate the number and density of molecules in the trap, which is Nm=44-110×10^3以及nm>5.2×10^11 cm^(-3). In order to improve the sensitivity of our detecting method, a longer trapping lifetime is needed. It was achieved by transporting atoms to an ultra-high vacuum chamber. In our apparatus, such a transportation of atoms was realized using a magnetic trap settled on a linear motor track. In the ultra-high vacuum chamber, the atomic lifetime is extended signi_cantly, and the collisions between atoms and molecules become more sensitive than the background residual gas collision. Several important characteristics of our apparatus was verified by producing the Bose-Einstein condensate (BEC) of 87Rb in a hybrid configuration: a single beam optical dipole trap within axial confinement supported by a weak magnetic trap. A pure condensate with 6.3×10^5 atoms are formed in this hybrid trap. This 87Rb BEC can be a refrigerant for the future sympathetic cooling with K, Rb2 and K2.