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We derive threshold equations for self-organization of laser driven atoms in an optical cavity. Our analysis includes probing with either a traveling wave or a retro reflected lattice. These two scenarios lead to qualitatively different behavior in t erms of the response of the system as a function of cavity detuning with respect to the probe. In addition our analysis includes the effects of an intra-cavity trapping potential which is also shown to impact on the threshold condition. We specifically consider the case of an intra-cavity lattice but our treatment can easily be modified to other geometries.
We study the transmission spectra of ultracold rubidium atoms coupled to a high-finesse optical cavity. Under weak probing with pi-polarized light, the linear response of the system is that of a collective spin with multiple levels coupled to a singl e mode of the cavity. By varying the atom number, we change the collective coupling of the system. We observe the change in transmission spectra when going from a regime where the collective coupling is much smaller than the separation of the atomic levels to a regime where both are of comparable size. The observations are in good agreement with a reduced model we developed for our system.
We report the all-optical production of a Rb87 Bose-Einstein condensate (BEC) in a simple 1.06 micron dipole trap experiment. We load a single beam dipole trap directly from a magneto-optic trap (MOT) using an optimized loading sequence. After evapor ation in the single beam, a second crossed beam is used for compression. The intensity in both beams is then reduced for evaporation to BEC. We obtain a BEC with 3.5E4 atoms after 3 seconds of total evaporation time. We also give a detailed account of the thermal distribution in cross beam traps. This account highlights the possible difficulties in using shorter wavelength lasers to condense all optically.
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