Abstract
Surface ripples generated by laser-induced surface electromagnetic waves (SEW) are causing interest because the dimensions of the microstructures that are formed are less than the wavelength of the laser light. The generation process is controlled by the laser wavelength used and the dispersion relationship of the SEW. A characteristic difference in the dependence of the ripple period on the incident angle between metals and semiconductors was observed using a femto-second laser. This difference is explained by the different coupling conditions of metals and semiconductors. In the case of metals, the wavenumber of the ripple is given by kSEW - k0sinθ. On the other hand, in the case of semiconductors, the wavenumber of the ripple is given by kSEW + k0sinθ.
