Sub-Doppler Spectroscopy of a vapour confined in an Extremely Thin Cell : Saturation effects and interplay between coherent resonances and incoherent losses

Saturation effects affecting absorption and fluorescence spectra of an atomic vapour confined in an extremely thin cell (cell thickness L< 1 mum) are investigated experimentally and theoretically. It is known that in a thin cell of dilute vapour, the wall-to-wall atomic trajectories generate original sub-Doppler signatures for spectra recorded under normal incidence.