High speed fabrication of periodical nanostructures by fs-laser direct writing on surfaces and in the volume of transparent materials

Using fs-laser direct writing periodical surface nanostructures are fabricated on the surface of dielectric materials. By using high repetition rate fs-laser radiation with a wavelength of 1045 nm periodical nanostructures with periods of 200-350 nm are obtained on dielectrics. In this paper the pump-probe technique is used for time-resolved investigations of the spectral reflectivity and transmittivity during and up to 1 ns after the fs-laser pulse. From this measurements the transient electron density in the conduction band and the transient dielectric function are calculated and used to extend the classical ripples theory with the transiently modified dielectric function. The periods of the surface nanostructures are compared to the calculations and discussed.