Periodical structures induced by femtosecond laser on metals in air and liquid environments

► The dependence of the surface morphology on laser fluence, the radiation wavelength and the irradiation conditions: air or liquid environment, was analyzed. ► In our experiments the period of structures formed in liquid are generally several times smaller than those formed in air. ► When samples are processed in air with 387 nm laser wavelength, the LIPSS periods are similar to those obtained in liquids at 775 nm.