Lateral self-limitation ofthe cw-laser-indnced local oxidation ofultrathin (3-60 nm,) titaniumfilms in air is studied It is shown, that the brightening ofiheflirns on transparent substrate upon through -oxidation f orms a negativefeedbcick to this highly-nonlinear process allowing stable writing oftransparent oxide line structures narrower than the diffraction lirniiedfocused laser spot. The optimum metaiflim thickness to obtain the greatest optical contrast with the highest resolulion is ofthe order ofthe light absorption length in the metal. Transparent isolated oxide lines and gratings with periocLc down to 250 nm and line width down to 165 nm were recorded in 6 -15 nni thick Tiflims on glass by using the radiation ofthe Ar ion laser (,Z=488, 514 nm).