| The application technology of femtosecond pulses with high peak power and short pulse width becomes an important study in the interaction of laser with materials, and ultrashort pulse of femtosecond laser also plays a significant role in various research. The diagnostic techniques based on ultrafast femtosecond laser provides new method for the various study of ultrafast physical process and chemical reaction. In this study,we use the pump-probe ultrafast diagnostic system to study the kinetics of ultrafast laser ablation fused silica.Its main contents are shown as follows:It mainly studys the ultrafast dynamics process of strong nanosecond laser ablation of fused silica optical components by using pump-probe ultrafast diagnostic systems based on signal generator.Propagation characteristics of the shock waves induced by nanosecond laser in material is investigated by ultrafast time-resolved optical diagnosis and studied based on the basic theories of the reflection and refraction of spherical waves across a planar interface. The evolution processes of time-resolved optical images of shock waves propagation in material and plasmas expansion in air are obtained. Moreover, the reflection and refraction waves will be yielded when the generated shock waves arrive at the surface of sample. Meanwhile, it found that the intensity of reflection and refraction waves at the interface is determined by the incident angle of shock wave, and the velocity of shock wave propagations in material are difference for different shock wave.Using the time-resolved optical diagnostic techniques based on optical delay line controlling, high-energy femtosecond laser ablation of different fused silica is studied. Plasma expansion and material ejection images are bserved to study the ultrafast dynamics of laser ablation process in a shorter delay time.In the femtosecond laser ablation fused silica process,nonlinear filamentation shadow and self-focusing phenomenon in transparent material are observed. |
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