Light-induced atomic desorption (LIAD) is a non-thermal process in which atoms adsorbed at a surface are released under illumination. It is applied mostly for realization of optical dispensers in the cases when high atomic density at low temperature is needed – for example, for loading atomic devices as atomic magnetometers, atomic clocks, magneto-optical traps and their miniaturization. However as desorption depends on the atom-surface interaction it can be applied for optical characterization and manipulation of alkali metal nanoparticles as well. In this work an experimental investigation of the shape of the transmission spectra and their dependence on the illuminating blue light power in PDMS coated cells prepared with two different con...