Currently, laser-induced structural modifications in optical materials have been an active field of research. In this paper, we reported structural modifications in the bulk of sapphire due to picosecond (ps) laser filamentation and analyzed the ionization dynamics of the filamentation. Numerical simulations uncovered that the high-intensity ps laser pulses generate plasma through multi-photon and avalanche ionizations that leads to the creation of two distinct types of structural changes in the material. The experimental bulk modifications consist of a void like structures surrounded by cracks which is followed by a submicrometer filamentary track. By increasing laser energy, length of the damage and filamentary track appeared to increase. In addition, the transverse diameter of the damage zone increased due to the electron plasma produced by avalanche ionizations, but no increase in the filamentary zone diameter was observed with increasing laser energy.
Ionization behavior and dynamics of picosecond laser filamentation in sapphire
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National Natural Science Foundation of China (51575013, 51275011) and National Key R & D Program of China (2018 YFB1107500)
引用本文： Amina, Ji L F, Yan T Y, Ma R. Ionization behavior and dynamics of picosecond laser filamentation in sapphire. Opto-Electron Adv 2, 190003 (2019).
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