抄録
The effect of surrounding air pressure and repeated irradiation on selective vaporization in laser induced shock wave plasma has been studied on brass target using tightly focused beam of a Q-switched Nd: YAG laser operated at 26 mJ. The vaporization effects of Zn and Cu were studied in terms of their emission characteristics. It was found out that selective vaporization in favor of Zn atoms always takes place under various conditions considered in this study and tends to enhance with the number of repeated irradiation on the same spot of the sample surface. On the other hand, this undesirable effect could be significantly suppressed by increasing the air pressure. These results as well as other features exhibited by the time-dependent emission intensities and the spatially integrated emission intensities have been shown to be explicable in terms of the shock excitation mechanism associated with the laser induced shock wave model.
