The light-induced desorption and diffusion of alkali-metal atoms in organic films are interesting fields of investigation. An impressive demonstration is given by the recently observed light-induced atomic desorption ͑LIAD͒ effect, where a huge alkali-metal atom desorption from siloxane films, previously exposed to atomic vapors, is induced by weak and nonresonant light. In this paper, experimental data and a one-dimensional theoretical model of the effect are presented. The model gives a good description of the vapor density dynamics by taking into account both the atomic diffusion inside the coating and the surface desorption. General equations are reported and discussed within the limits of experimental interest. The potential barrier at the vapor-surface interface and the activation energy for Rb in ͑poly͒dimethylsiloxane have been determined. ͓S1050-2947͑99͒01512-7͔

Coherent population trapping resonances in cesium vapor can be used to determine DC flux densities in the range from 1 µT to 1 mT with typically 3•10 −5 relative uncertainty. For fields modulated at a few kHz, we find sensitivities of below 10 pT within 0.5 s integration time. From the signal-to-noise ratio the sensitivity can be extrapolated to 500 fT/ √ Hz. A quantitative understanding of the lineshape allows to detect DC fields of several nT even when the Zeeman components of the resonance are not resolved.

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A multi-channel atomic magnetometer operating in an unshielded environment is described and characterised. The magnetometer is based on D1 optical pumping and D2 polarimetry of Cs vapour contained in gas-buffered cells. Several technical implementations are described and discussed in detail. The demonstrated sensitivity of the setup is 100 fT/ √ Hz when operating in the difference mode.

We present encouraging results obtained with an experimental apparatus based on coherent population trapping\ud and aimed at detecting a biological (cardiac) magnetic field in a magnetically compensated but unshielded\ud volume. The work includes magnetic-field and magnetic-field-gradient compensation and uses differential detection\ud to cancel common mode magnetic noise. Synchronous data acquisition with a reference (electrocardiographic\ud or pulse-oximetric) signal makes possible improvement of the signal-to-noise ratio in off-line averaging.\ud The setup has the significant advantages of working at room temperature with a small-size head, and the\ud possibility of fast adjustments of the dc bias magnetic field, which makes the sensor suitable for detecting a\ud biomagnetic signal at any orientation with respect to the axis of the head and in any position on the patient’s\ud chest, which is not the case with other kinds of magnetometers