A fluorescence detection scheme coupled to a highly sensitive nitrogen-cooled CCD camera is used to image the spatial distribution of a low-density falling rubidium atomic cloud released from an optical trap. The falling cloud passes through a thin probe laser beam tuned to resonance. The performance of the scheme is illustrated in the analysis of cold atomic clouds collimated by pinholes during their free fall under the influence of gravity. Clouds of approximately 10<sup>4</sup> atoms and with typically 10<sup>6</sup> at./cm<sup>3</sup> density are analyzed spatially with 24-μm resolution. This method is compared with different atomic cloud imaging techniques.
© 1998 Optical Society of America
(010.1290) Atmospheric and oceanic optics : Atmospheric optics
(040.1520) Detectors : CCD, charge-coupled device
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(140.2020) Lasers and laser optics : Diode lasers
Isabelle Serre, Laurence Pruvost, and Hong Tuan Duong, "Fluorescence Imaging Efficiency of Cold Atoms in Free Fall," Appl. Opt. 37, 1016-1021 (1998)