We report on experiments on Rydberg–Rydberg interaction-induced effects in a gas of 87Rb Rydberg atoms. A compact setup for two-photon continuous-wave excitation of high-lying Rydberg states out of an ultracold atomic gas is presented. The performance of the apparatus is characterized by high-resolution spectroscopy of Rydberg states. Signatures of interaction-induced effects are identified by qualitatively analysing the dependence of Rydberg excitation spectra on the intensity and the duration of the second-step laser excitation.

We have realized a two-species mirror-magneto-optical trap containing a mixture of 87 Rb ͑ 85 Rb͒ and 133 Cs atoms. Using this trap, we have measured the heteronuclear collisional loss rate ␤ Rb-Cs Ј due to intraspecies cold collisions. We find a distinct difference in the magnitude and intensity dependence of ␤ Rb-Cs Ј for the two isotopes 87 Rb and 85 Rb which we attribute to the different ground-state hyperfine splitting energies of the two isotopes.

We have used an optical fiber based system to implement optical detection of atoms trapped on a reflective "atom-chip". A fiber pair forms an emitter-detector setup that is bonded to the atom-chip surface to optically detect and probe laser cooled atoms trapped in a surface magneto-optical trap. We demonstrate the utility of this scheme by measuring the linewidth of the Cs D2 line at different laser intensities.