Surface modification of ASP 30 steel induced by femtosecond laser with 10(14) and 10(13) W/cm(2) intensity in vacuum

Abstract

A study of ASP 30 steel surface modification with high intensity Ti:sapphire laser, operating at 804 nm wavelength and pulse duration of 60 fs, in vacuum ambient, is presented. ASP 30 steel surface variations were studied at laser intensities of 10(14) and 10(13) W/cm(2). The steel target specific surface changes and phenomena observed are: (i) Creation of craters at 10(14) W/cm(2) intensity; (ii) formation of periodic surface structures only at the reduced intensity of 10(13) W/cm(2); (iii) chemical surface changes registered only at higher laser intensity, and (iv) occurrence of plasma in front of the surface, including its emission in X-ray region. It can be concluded from this study that the reported laser intensities can effectively be applied for ASP 30 steel surface modification. Careful choosing of laser intensity and pulse count can lead to precise superficial material removal, for example laser intensity similar to 10(13) W/cm(2) and low pulse count can lead to ultra-precise surface processing. Generally, femtosecond laser surface modification of ASP 30 steel is non-contact and very rapid compared with traditional modification methods.