Eur. Phys. J. AP
Volume 5, Number 2, February 1999
|Page(s)||163 - 169|
|Published online||15 February 1999|
Time-resolved studies of short pulse laser-produced plasmas in silicon dioxide near breakdown threshold
Laboratoire d'Optique Appliquée (LOA) (UMR 7639
CNRS), École Polytechnique, ENSTA, rue de la Hunière, 91167 Palaiseau, France
2 Laboratoire pour l'Utilisation des Lasers Intenses (LULI) (UMR 7605 CNRS), École Polytechnique, CEA, Université Paris VI, 91128 Palaiseau, France
Revised: 29 October 1998
Accepted: 29 October 1998
Published online: 15 February 1999
Using the technique of frequency-domain interferometry, we demonstrate a new way of studying laser-induced breakdown at the surface of dielectric materials. A theoretical model based on electron production by multiphoton ionisation, inverse bremsstrahlung heating, and collisional ionisation is in quantitative agreement with both the detailed time variation of the dielectric constant and the pulse width variation of the fluence threshold. From the complex reflection coefficient measured with the two probe pulse polarisations in quadrature, we deduce the time variation of the dielectric constant of silica during breakdown.
PACS: 52.50.Jm – Plasma production and heating by laser beams / 78.47.+p – Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter / 77.22.Jp – Dielectric breakdown and space-charge effects
© EDP Sciences, 1999
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