Femtosecond laser induced surface structures on amorphous alloys

We investigate the formation of micro- and nano-structures induced by femtosecond laser pulses on the surface of amorphous alloys. Periodic ripples aligned perpendicular to the direction of laser polarization has been observed. Particularly aperiodic ripples with orientation parallel to the laser polarization are formed depend on the number of laser pulses. Nanoripples with orientation parallel to the laser polarization are formed over the entire laser-scanned regions. Measurement of X-ray diffraction shows that the amorphous structures still keep their original amorphous states.