Control of Filament by Shaped Femtosecond Pulses in Fused Silica

The pulse shaping technology based on liquid crystal spatial light modulator is used to control the femtosecond laser filament in fused silica. The experimental results show that the filament can be generated at a designated position in fused silica. In addition, a long-distance controllable displacement of the onset of filamentation in fused silica is achieved, with a maximum displacement of 5.4 mm. Furthermore, the theoretical simulation on filamentation of shaped pulse in fused silica is performed based on the (3 1)-1) nonlinear Schrodinger equation. The results arc consistent with those of experiments. It is demonstrated that the onset of filamentation depends on the peak intensity and envelope of shaped femtosecond pulse.