Dynamical Studies on Laser Processes Induced by Short Pulse Lasers: From Nanoseconds to Milliseconds

Laser processes induced by short pulse lasers are widely applied in industries and research fields. Details of these processes depend on the laser wavelength and pulse duration of lasers used, materials irradiated, irradiation conditions such like power density and repetition rate and other parameters. To elucidate the details of these processes, we have developed a technique, which is named as high-speed laser stroboscopic videography, to take fast videos to visualize these processes. By combining a newly developed high-speed video cameras and high-repetition rate short pulse lasers, the technique allows us to take videos as fast as 1 μs interval in several recording modes, and gives unique information on several laser processes. In this paper we presents some examples of such studies on laser peening, dynamics of laser-induced bubbles in liquids, and micromachining on hard and brittle materials by a femtosecond laser.