Fabrication of complex micro/nanopatterns on semiconductors by the multi-beam interference of femtosecond laser

Short periodic nanostructures with periods much smaller than the laser wavelength (1/10-1/2 lambda) are fabricated on semiconductors after femtosecond laser irradiation. Laser polarization is an important factor to influence the formation of laser-induced nanostructures. Combining the fabrication of short periodic nanostructures induced by femtosecond laser with multi-beam interference, different types of complex micro/nanopattems have been induced by the two-, three- and four-beam interferences of femtosecond laser with the modification of laser polarization combinations. The micro/nanopattems are composed of two parts: two-dimensional long periodic micro-patterns and short periodic nano-patterns. Theoretical calculations of interferential polarization and intensity patterns for different polarization combinations explain well the experimental results. These researches have potential applications in the nanopatteming of semiconductors. (C) 2014 Published by Elsevier B.V.