An epitaxial lithium niobate (LiNbO3) thin film was successfully fabricated on an alpha -Al2O3(0 0 0 1) substrate using a pulsed laser deposition method and me effect of laser fluence on film quality was investigated. The Li concentration in a deposited Sim was largely influenced by oxygen radicals, which were produced not only by the interaction between the incident excimer laser and the oxygen but also by an rf-radical source: The re-evaporation of Li atoms in the film was suppressed by the oxidation of Li atoms.