The dielectric constant and the reflectivity spectrum of polycrystallineRuO2films, grown by pulsed laser deposition, are presented as deduced by optical reflection and electron energy-loss spectroscopy. The similarities of these spectra with those obtained on single crystals, suggest that the production ofRuO2by laser ablation is a very good tool in obtaining films with electronic and structural characteristics equivalent to those of the bulk material. ©1997 American Institute of Physics.