Ultraviolet laser irradiation induced chemical reactions of some metal oxides

The interaction of ultraviolet laser light of wavelength 308 nm and a pulse length of 28 ns with 24 inorganic oxides was studied. The laser fluence was varied between 0.009 and 4 J cm(-2). The visible result of the laser impulse could be divided into three categories. A number of oxides, CeO2, TiO2, Nb2O5, MoO3 and WO3, gave intense blue-black marks under irradiation. The oxides V2O5, Cr2O3, Fe2O3, NiO, CuO, CdO and Tl2O3 gave dark silver-metallic marks. The third group, consisting of MgO, ZrO2, Ta2O5, ZnO, Al2O3, Ga2O3, Sb2O4, In2O3, SnO2, Y2O3, Eu2O3 and Sm2O3, did not mark or showed a brownish discoloration. The reactions that occurred, especially any darkening, could be correlated with the non-stoichiometric nature of the oxides.