| Investigations of optical processes for laser cooled and trapped atoms are described. Fluorescence from Cs atoms in a magneto-optical trap is detected under conditions of very low atomic density. Discrete steps are observed in the fluorescent signal versus time and are associated with the arrival and departure of individual trapped atoms. Histograms of the frequency of occurrence of a given level of fluorescence exhibit a series of uniformly spaced peaks that are attributed to the presence of N = 0, 1,2 atoms in the trap.; In addition, numerical absorption and emission spectra for three-level {dollar}Lambda , Xi ,{dollar} and V systems under intense radiations are calculated. Absorption spectra for a {dollar}Lambda{dollar} system is used to explain the probe-wave amplification and absorption spectra recorded for Cs atoms cooled and confined in a magnet optical trap, in which novel spectral features of narrow frequency widths with single-pass gain exceeding 20% are observed. The consequence of the optical gain is demonstrated to lead to negative radiation pressure, which is investigated together with other mechanical forces in the trap. Various alternative trapping schemes in three-level and two-level atoms are proposed as possible means to compress an atomic sample and demonstrated for a two-level magneto-optical trap. |
