Efficiency of the Laser-Induced Breakdown Spectroscopy (LIBS) has been studied as applied to the development of a
technique for elemental microanalysis of solid samples, when a rather low consumption of the sample material is
demanded allowing the technique to be practically non-destructive and applicable, e.g., at art, archaeological, forensic
and similar investigations of unique objects. Higher intensity of the laser-induced emission spectra at lower sample
erosion result in the increased efficiency of the LIBS analysis. The efficiency depends on many factors and in particular
on thermal properties of the sample material and on its excitation conditions. Here, an influence of the laser beam
focusing has been studied for samples of Al and Pb alloys having different thermal properties.