Dynamics of filamentary damage induced by nanosecond laser in fused silica

The phenomena and mechanisms of energy deposition and plasma shielding during laser breakdown of transparent dielectrics deserve further discussion. In this work, the formation characteristics of 1064 nm ns pulsed laser-induced fused silica filamentary damage behavior during the bulk damage process were studied using the time-resolved pump-probe technique. The role of plasma shielding in the damage process was also further studied. The results indicate that the filamentary damage formed before the core damage. With the enhancement of laser energy, the filamentary damage length is stable in the initial stage and then begins to grow dramatically, and the core damage location moves towards the front surface of the fused silica. However, the plasma scattering and shielding effects in air and fused silica severely affect the damaged region when the laser energy is further enhanced. It causes rapid decay of the filamentary damage length, while the core damage moves along the optical axis to the rear surface of the fused silica. It was also found that the diameter of the filamentary damage was not significantly affected by the relatively small laser energy.