화학공학소재연구정보센터
Applied Surface Science, Vol.255, No.17, 7556-7560, 2009
Surface micro/nanostructuring of titanium under stationary and non-stationary femtosecond laser irradiation
In this paper the surface topography of titanium samples irradiated by femtosecond laser pulses is described. When the fluence is about 0.5 J/cm(2) periodic ripples with a period of about 700 nm are formed. For fluences between 0.5 and 2 J/cm(2), a microcolumnar surface texture develops in the center of the irradiated spots and ripples are formed in the periphery of the spots. When experiments are performed with a non-stationary sample, the microcolumns exhibit ripples similar to those observed when the radiation fluence is about 0.5 J/cm(2) and in the outer regions of the irradiated areas for fluences between 0.5 and 2 J/cm(2). Since the energy distribution in the transverse cross-section of the laser beam is Gaussian, we conclude that the ripples form when the microcolumns are subjected to fluences near the melting threshold of the material at the trailing edge of the moving laser beam. (C) 2009 Elsevier B.V. All rights reserved.