Ultrafast Laser Writing Deep inside Silicon with THz-Repetition-Rate Trains of Pulses
Analyses of the energy densities achieved in Si with different number of pulses in the trains. Different number of pulses from 1 to 64 in the applied THz burst: (a) delivered peak fluence (P.F.) inside Si as a function of burst energy; (b) maximum peak delivered fluence (MPF), laser-induced damage threshold (LIDT), and ratio between them; (c) total burst energies as a function of propagation distance inside Si (zero position representing the geometrical focusing plane). The red box part is further analyzed in (d) showing the pulse energy reduction per distance unit (, blue) and the apparent beam size (, half maximum area, red curve) in the first row and corresponding absorbed energy densities () at different positions in the second row.