Improvement of laser-induced damage thresholds of aluminum by using a unique electropolishing method

Surfaces of polycrystalline Al samples were treated by using electropolishing, etching or mechanical polishing methods. Surface morphologies, laser-induced damage thresholds (LIDTs) and ejected particle numbers of different samples were analyzed and compared. Results showed that several different surface morphologies of Al were prepared. A new surface electropolishing technique was developed and an improvement of 95% of LIDT of Al was obtained by using this method. Ejected particle numbers of different samples were monitored and compared to investigate their damage-resistant properties. The particle numbers ejected from the electropolished sample are much smaller than those of etched or mechanically polished samples under Q-switched 355-nm Nd:YAG laser irradiation at 6.8 ns pulses.