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

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The influence of excimer laser irradiation (193 nm, 20 ns pulses and 248 nm, 20 ns and 500 fs pulses) on the structure and morphology of plain and gold-film coated mica surfaces has been investigated for fluences between 8 mJ/c2 and 19 J/cm2. Surfaces treated with laser fluences below the ablation threshold (λ=248 nm) are well suited for controlled growth of metallic films, whereas above-threshold treated samples (λ=193 nm) form roughened surfaces with close-packed arrays of cones. The cone generation can be suppressed by appropriate choice of laser parameters, resulting in the formation of ablation holes with micrometer precision. The same precision can be obtained in ultrathin metallic films without destroying the underlying mica surface. Low-energy electron diffraction is used to monitor laser-induced microscopic changes of the mica surface upon low-fluence irradiation. It is seen that the first step of the ablation process includes reorientation of dipole domains on the surface. Thereafter, scanning electron microscopy reveals melting of the surface and the onset of explosive sputtering processes. Studies of the ablated products by the use of quadrupole mass spectrometry, quartz microbalance, and photoimaging indicate large kinetic energies and a high directionality of the ablated products.

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