Light-induced atomic desorption from porous silica

Huge light-induced rubidium atom desorption has been observed from poroussilica samples placed inside Pyrex cells kept at room temperature. The desorption rate andthe maximum vapour density change have been measured as a function of the desorbing lightintensity. Their values are comparable with those recently obtained in Pyrex cells coated withorganic films. A linear dependence of the desorption rate and a square-root dependence of themaximum density increase on light intensity indicate that diffusion inside the glass pores isa key mechanism. The application of this effect to develop light-controlled atomic dispenserscompatible with high vacuum environment is discussed.