The dynamics of magneto-optical trap loading by light-induced atom desorption (LIAD) are investigated theoretically and experimentally. The loading of the MOT has been described by a theoretical model. We have paid close attention to the background gases which are essentially important for the ultimate vacuum pressure. The experiment is done based on a glass cell and all the results are well in agreement with the theory. The decay process of the background vacuum pressure caused by the untrapped cesium atoms after shutting off the desorption light is explained quantitatively. The LIAD effect is proved to be an effective tool to control the loading of the MOT and the neutral single atoms in experiment.
We show that light-induced atom desorption (LIAD) can be used as a flexible atomic source for large
87Rb and
40K magneto-optical traps. The use of LIAD at short wavelengths allows for fast switching of the desired vapor pressure and permits experiments with long trapping and coherence times. The wavelength dependence of the LIAD effect for both species was explored in a range from
630to253nm in an uncoated quartz cell and a stainless steel chamber. Only a few
mW∕cm2 of near-UV light produce partial pressures that are high enough to saturate a magneto-optical trap at $3.5\ifmmode\times\else\texttimes\fi{}{10}^{9}$
87Rb atoms or $7\ifmmode\times\else\texttimes\fi{}{10}^{7}$
40K atoms. Loading rates as high as $1.2\ifmmode\times\else\texttimes\fi{}{10}^{9}$
87Rb atoms/s and $8\ifmmode\times\else\texttimes\fi{}{10}^{7}$
40K atoms/s were achieved without the use of a secondary atom source. After the desorption light is turned off, the pressure quickly decays back to equilibrium with a time constant as short as $200\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$, allowing for long trapping lifetimes after the MOT loading phase.