Plasma formation and relaxation dynamics in fused silica driven by femtosecond short-wavelength infrared laser pulses

P. Jürgens (1) , M. Vrakking (2) , R. Stoian (3) , A. Mermillod-Blondin (2)

1 MBI - Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie
2 MBI - Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy
3 LHC - Laboratoire Hubert Curien

Laser-induced plasma formation and subsequent relaxation in solid dielectrics is the precursor to structural modifications that are accompanied by a permanent alteration of material properties. The decay of the electron-hole plasma through distinct relaxation channels determines the properties of the resulting modification. Based on an experimental arrangement combining a time-resolved transmission measurement with a cross-phase modulation measurement, we isolate the plasma formation and relaxation dynamics in the bulk of amorphous fused silica excited by femtosec-ond short-wavelength infrared (λ = 2100 nm) laser pulses. Whereas the relaxation time of the generated electron-hole plasma was so far assumed to be constant, our findings indicate an intensity-dependent relaxation time. We attribute this intensity dependence to vibrational detrapping of self-trapped excitons.

Domaines: Optique / photonique

P. Jürgens, M. Vrakking, R. Stoian, A. Mermillod-Blondin. Plasma formation and relaxation dynamics in fused silica driven by femtosecond short-wavelength infrared laser pulses. Applied Physics Letters, 2019, 115 (19), pp.191903. ⟨10.1063/1.5117837⟩. ⟨ujm-02354599⟩