Femtosecond laser ablation of thin silver films in air and water under tight focusing

In this work, microscale holes and intermediate self-organized structures were obtained on the surface of a thin 50-nm silver film in air and under a water layer using single tightly focused femtosecond laser pulses with variable energy. We study the differences in the relief of microholes using scanning electron microscopy. The comparison of the silver film ablation thresholds under irradiation in air and water is carried out. A non-monotonic change in the size of craters in a water medium at peak powers more than 1.5MW was found, which corresponds to the critical filamentation power of laser pulses in water.