Formation of Periodic Nanostructures on ZnO Surface Induced by Single Femotsecond Laser Beam

The formation of periodic nanostructures on ZnO surface induced by femtosecond laser pulses at different wavelengths is reported in this paper.The relationship between the periods of nanostructures Λ and laser wavelengths λ is studied,giving a linear relation Λ=λ/2n,where n is the refractive index of the sample.It is proposed that the sample should be separated into a surface layer and a subsurface layer to explain the formation mechanism of the periodic nanostructures induced by femtosecond laser.