LATERAL SELF-LIMITATION IN THE LASER-INDUCED OXIDATION OF ULTRATHIN METAL-FILMS

cw-laser-induced local oxidation of ultrathin (3-60 nm) titanium films on glass in air is studied, It is shown. that the brightening of the films upon through-oxidation forms a negative feedback to this highly nonlinear process. It offers the possibility of stable writing of oxid e line structures narrower than the diffraction limited focused laser spot. The optimum metal film thickness is of the order of the light ab sorption length in the metal. Transparent isolated oxide lines and gra tings with periods down to 250 nm and line width down to 165 nm were r ecorded in 6-15 nm thick Ti films on glass by using the radiation of t he Ar ion laser (lambda=488, 514 nm). (C) 1996 American Institute of P hysics.