Laser‐induced breakdown by impact ionization in SiO2with pulse widths from 7 ns to 150 fs

D. Du, X. Liu, G. Korn, J. Squier, G. Mourou
1994 Applied Physics Letters  
Results of laser-induced breakdown experiments in fused silica (SiOJ employing 150 fs-7 ns, 780 mn laser pulses are reported. The avalanche ionization mechanism is found to dominate over the entire pulse-width range. Fluence breakdown threshold does not follow the scaling of F,-6, when pulses are shorter than 10 ps. The impact ionization coefficient of SiO, is measured up to -3 X 10' V/cm. The relative role of photoionization in breakdown for ultrashort pulses is discussed. Laser-induced
more » ... aser-induced breakdown (LIB) in optically transparent materials has been studied extensively since the laser was invented in the 1960s1-' LIB mechanisms have been inves-
doi:10.1063/1.111350 fatcat:wi22oqz6arg4dbmdtnzuskgm5y