Time-resolved pump-probe interferometry of femtosecond-laser-induced phenomena

We use an interferometric time-resolved observation of a femtosecond-laser pulse interaction with glass from 100 fs to 10 ns at submicrometer spatial lateral resolution. The phase and amplitude images reveal sequence of events after the irradiation of a single ultra-short laser pulse at close-to-threshold intensity when permanent refractive index changes occur. The proposed method is applicable to characterization of the processes induced by tightly focused fs-laser pulses during three-dimensional structuring of glasses and crystals for fundamental studies and optical applications. Generation of carriers, thermal expansion, generation and propagation of shockwaves, and formation of refractive index changes are experimentally observed and resolved in time and space with the highest resolution.